1/* 2 * Copyright (c) 2007 Mockito contributors 3 * This program is made available under the terms of the MIT License. 4 */ 5package org.mockito; 6 7import org.mockito.internal.InternalMockHandler; 8import org.mockito.internal.MockitoCore; 9import org.mockito.internal.creation.MockSettingsImpl; 10import org.mockito.internal.debugging.MockitoDebuggerImpl; 11import org.mockito.internal.framework.DefaultMockitoFramework; 12import org.mockito.internal.session.DefaultMockitoSessionBuilder; 13import org.mockito.internal.verification.VerificationModeFactory; 14import org.mockito.invocation.Invocation; 15import org.mockito.invocation.InvocationFactory; 16import org.mockito.invocation.MockHandler; 17import org.mockito.junit.MockitoJUnit; 18import org.mockito.junit.MockitoJUnitRunner; 19import org.mockito.junit.MockitoRule; 20import org.mockito.listeners.VerificationStartedEvent; 21import org.mockito.listeners.VerificationStartedListener; 22import org.mockito.mock.SerializableMode; 23import org.mockito.plugins.MockMaker; 24import org.mockito.plugins.MockitoPlugins; 25import org.mockito.quality.MockitoHint; 26import org.mockito.quality.Strictness; 27import org.mockito.session.MockitoSessionBuilder; 28import org.mockito.session.MockitoSessionLogger; 29import org.mockito.stubbing.Answer; 30import org.mockito.stubbing.Answer1; 31import org.mockito.stubbing.OngoingStubbing; 32import org.mockito.stubbing.Stubber; 33import org.mockito.stubbing.Stubbing; 34import org.mockito.stubbing.VoidAnswer1; 35import org.mockito.verification.After; 36import org.mockito.verification.Timeout; 37import org.mockito.verification.VerificationAfterDelay; 38import org.mockito.verification.VerificationMode; 39import org.mockito.verification.VerificationWithTimeout; 40 41/** 42 * <p align="left"><img src="logo.png" srcset="logo@2x.png 2x" alt="Mockito logo"/></p> 43 * The Mockito library enables mock creation, verification and stubbing. 44 * 45 * <p> 46 * This javadoc content is also available on the <a href="http://mockito.org">http://mockito.org</a> web page. 47 * All documentation is kept in javadocs because it guarantees consistency between what's on the web and what's in the source code. 48 * It allows access to documentation straight from the IDE even if you work offline. 49 * It motivates Mockito developers to keep documentation up-to-date with the code that they write, 50 * every day, with every commit. 51 * 52 * <h1>Contents</h1> 53 * 54 * <b> 55 * <a href="#0">0. Migrating to Mockito 2</a><br/> 56 * <a href="#0.1">0.1 Mockito Android support</a></br/> 57 * <a href="#0.2">0.2 Configuration-free inline mock making</a></br/> 58 * <a href="#1">1. Let's verify some behaviour! </a><br/> 59 * <a href="#2">2. How about some stubbing? </a><br/> 60 * <a href="#3">3. Argument matchers </a><br/> 61 * <a href="#4">4. Verifying exact number of invocations / at least once / never </a><br/> 62 * <a href="#5">5. Stubbing void methods with exceptions </a><br/> 63 * <a href="#6">6. Verification in order </a><br/> 64 * <a href="#7">7. Making sure interaction(s) never happened on mock </a><br/> 65 * <a href="#8">8. Finding redundant invocations </a><br/> 66 * <a href="#9">9. Shorthand for mocks creation - <code>@Mock</code> annotation </a><br/> 67 * <a href="#10">10. Stubbing consecutive calls (iterator-style stubbing) </a><br/> 68 * <a href="#11">11. Stubbing with callbacks </a><br/> 69 * <a href="#12">12. <code>doReturn()</code>|<code>doThrow()</code>|<code>doAnswer()</code>|<code>doNothing()</code>|<code>doCallRealMethod()</code> family of methods</a><br/> 70 * <a href="#13">13. Spying on real objects </a><br/> 71 * <a href="#14">14. Changing default return values of unstubbed invocations (Since 1.7) </a><br/> 72 * <a href="#15">15. Capturing arguments for further assertions (Since 1.8.0) </a><br/> 73 * <a href="#16">16. Real partial mocks (Since 1.8.0) </a><br/> 74 * <a href="#17">17. Resetting mocks (Since 1.8.0) </a><br/> 75 * <a href="#18">18. Troubleshooting & validating framework usage (Since 1.8.0) </a><br/> 76 * <a href="#19">19. Aliases for behavior driven development (Since 1.8.0) </a><br/> 77 * <a href="#20">20. Serializable mocks (Since 1.8.1) </a><br/> 78 * <a href="#21">21. New annotations: <code>@Captor</code>, <code>@Spy</code>, <code>@InjectMocks</code> (Since 1.8.3) </a><br/> 79 * <a href="#22">22. Verification with timeout (Since 1.8.5) </a><br/> 80 * <a href="#23">23. Automatic instantiation of <code>@Spies</code>, <code>@InjectMocks</code> and constructor injection goodness (Since 1.9.0)</a><br/> 81 * <a href="#24">24. One-liner stubs (Since 1.9.0)</a><br/> 82 * <a href="#25">25. Verification ignoring stubs (Since 1.9.0)</a><br/> 83 * <a href="#26">26. Mocking details (Improved in 2.2.x)</a><br/> 84 * <a href="#27">27. Delegate calls to real instance (Since 1.9.5)</a><br/> 85 * <a href="#28">28. <code>MockMaker</code> API (Since 1.9.5)</a><br/> 86 * <a href="#29">29. BDD style verification (Since 1.10.0)</a><br/> 87 * <a href="#30">30. Spying or mocking abstract classes (Since 1.10.12, further enhanced in 2.7.13 and 2.7.14)</a><br/> 88 * <a href="#31">31. Mockito mocks can be <em>serialized</em> / <em>deserialized</em> across classloaders (Since 1.10.0)</a></h3><br/> 89 * <a href="#32">32. Better generic support with deep stubs (Since 1.10.0)</a></h3><br/> 90 * <a href="#33">33. Mockito JUnit rule (Since 1.10.17)</a><br/> 91 * <a href="#34">34. Switch <em>on</em> or <em>off</em> plugins (Since 1.10.15)</a><br/> 92 * <a href="#35">35. Custom verification failure message (Since 2.1.0)</a><br/> 93 * <a href="#36">36. Java 8 Lambda Matcher Support (Since 2.1.0)</a><br/> 94 * <a href="#37">37. Java 8 Custom Answer Support (Since 2.1.0)</a><br/> 95 * <a href="#38">38. Meta data and generic type retention (Since 2.1.0)</a><br/> 96 * <a href="#39">39. Mocking final types, enums and final methods (Since 2.1.0)</a><br/> 97 * <a href="#40">40. (*new*) Improved productivity and cleaner tests with "stricter" Mockito (Since 2.+)</a><br/> 98 * <a href="#41">41. (**new**) Advanced public API for framework integrations (Since 2.10.+)</a><br/> 99 * <a href="#42">42. (**new**) New API for integrations: listening on verification start events (Since 2.11.+)</a><br/> 100 * <a href="#43">43. (**new**) New API for integrations: <code>MockitoSession</code> is usable by testing frameworks (Since 2.15.+)</a><br/> 101 * <a href="#44">44. Deprecated <code>org.mockito.plugins.InstantiatorProvider</code> as it was leaking internal API. it was replaced by <code>org.mockito.plugins.InstantiatorProvider2 (Since 2.15.4)</code></a><br/> 102 * </b> 103 * 104 * <h3 id="0">0. <a class="meaningful_link" href="#mockito2" name="mockito2">Migrating to Mockito 2</a></h3> 105 * 106 * In order to continue improving Mockito and further improve the unit testing experience, we want you to upgrade to 2.1.0! 107 * Mockito follows <a href="http://semver.org/">semantic versioning</a> and contains breaking changes only on major version upgrades. 108 * In the lifecycle of a library, breaking changes are necessary 109 * to roll out a set of brand new features that alter the existing behavior or even change the API. 110 * For a comprehensive guide on the new release including incompatible changes, 111 * see '<a href="https://github.com/mockito/mockito/wiki/What%27s-new-in-Mockito-2">What's new in Mockito 2</a>' wiki page. 112 * We hope that you enjoy Mockito 2! 113 * 114 * <h3 id="0.1">0.1. <a class="meaningful_link" href="#mockito" name="mockito-android">Mockito Android support</a></h3> 115 * 116 * With Mockito version 2.6.1 we ship "native" Android support. To enable Android support, add the `mockito-android` library as dependency 117 * to your project. This artifact is published to the same Mockito organization and can be imported for Android as follows: 118 * 119 * <pre class="code"><code> 120 * repositories { 121 * jcenter() 122 * } 123 * dependencies { 124 * testCompile "org.mockito:mockito-core:+" 125 * androidTestCompile "org.mockito:mockito-android:+" 126 * } 127 * </code></pre> 128 * 129 * You can continue to run the same unit tests on a regular VM by using the `mockito-core` artifact in your "testCompile" scope as shown 130 * above. Be aware that you cannot use the <a href="#39">inline mock maker</a> on Android due to limitations in the Android VM. 131 * 132 * If you encounter issues with mocking on Android, please open an issue 133 * <a href="https://github.com/mockito/mockito/issues/new">on the official issue tracker</a>. 134 * Do provide the version of Android you are working on and dependencies of your project. 135 * 136 * <h3 id="0.2">0.2. <a class="meaningful_link" href="#mockito-inline" name="mockito-inline">Configuration-free inline mock making</a></h3> 137 * 138 * Starting with version 2.7.6, we offer the 'mockito-inline' artifact that enables <a href="#39">inline mock making</a> without configuring 139 * the MockMaker extension file. To use this, add the `mockito-inline` instead of the `mockito-core` artifact as follows: 140 * 141 * <pre class="code"><code> 142 * repositories { 143 * jcenter() 144 * } 145 * dependencies { 146 * testCompile "org.mockito:mockito-inline:+" 147 * } 148 * </code></pre> 149 * 150 * Be aware that this artifact may be abolished when the inline mock making feature is integrated into the default mock maker. 151 * 152 * <p> 153 * For more information about inline mock making, see <a href="#39">section 39</a>. 154 * 155 * <h3 id="1">1. <a class="meaningful_link" href="#verification" name="verification">Let's verify some behaviour!</a></h3> 156 * 157 * The following examples mock a List, because most people are familiar with the interface (such as the 158 * <code>add()</code>, <code>get()</code>, <code>clear()</code> methods). <br> 159 * In reality, please don't mock the List class. Use a real instance instead. 160 * 161 * <pre class="code"><code class="java"> 162 * //Let's import Mockito statically so that the code looks clearer 163 * import static org.mockito.Mockito.*; 164 * 165 * //mock creation 166 * List mockedList = mock(List.class); 167 * 168 * //using mock object 169 * mockedList.add("one"); 170 * mockedList.clear(); 171 * 172 * //verification 173 * verify(mockedList).add("one"); 174 * verify(mockedList).clear(); 175 * </code></pre> 176 * 177 * <p> 178 * Once created, a mock will remember all interactions. Then you can selectively 179 * verify whatever interactions you are interested in. 180 * </p> 181 * 182 * 183 * 184 * <h3 id="2">2. <a class="meaningful_link" href="#stubbing" name="stubbing">How about some stubbing?</a></h3> 185 * 186 * <pre class="code"><code class="java"> 187 * //You can mock concrete classes, not just interfaces 188 * LinkedList mockedList = mock(LinkedList.class); 189 * 190 * //stubbing 191 * when(mockedList.get(0)).thenReturn("first"); 192 * when(mockedList.get(1)).thenThrow(new RuntimeException()); 193 * 194 * //following prints "first" 195 * System.out.println(mockedList.get(0)); 196 * 197 * //following throws runtime exception 198 * System.out.println(mockedList.get(1)); 199 * 200 * //following prints "null" because get(999) was not stubbed 201 * System.out.println(mockedList.get(999)); 202 * 203 * //Although it is possible to verify a stubbed invocation, usually <b>it's just redundant</b> 204 * //If your code cares what get(0) returns, then something else breaks (often even before verify() gets executed). 205 * //If your code doesn't care what get(0) returns, then it should not be stubbed. Not convinced? See <a href="http://monkeyisland.pl/2008/04/26/asking-and-telling">here</a>. 206 * verify(mockedList).get(0); 207 * </code></pre> 208 * 209 * <ul> 210 * <li> By default, for all methods that return a value, a mock will return either null, 211 * a primitive/primitive wrapper value, or an empty collection, as appropriate. 212 * For example 0 for an int/Integer and false for a boolean/Boolean. </li> 213 * 214 * <li> Stubbing can be overridden: for example common stubbing can go to 215 * fixture setup but the test methods can override it. 216 * Please note that overridding stubbing is a potential code smell that points out too much stubbing</li> 217 * 218 * <li> Once stubbed, the method will always return a stubbed value, regardless 219 * of how many times it is called. </li> 220 * 221 * <li> Last stubbing is more important - when you stubbed the same method with 222 * the same arguments many times. 223 * Other words: <b>the order of stubbing matters</b> but it is only meaningful rarely, 224 * e.g. when stubbing exactly the same method calls or sometimes when argument matchers are used, etc.</li> 225 * 226 * </ul> 227 * 228 * 229 * 230 * <h3 id="3">3. <a class="meaningful_link" href="#argument_matchers" name="argument_matchers">Argument matchers</a></h3> 231 * 232 * Mockito verifies argument values in natural java style: by using an <code>equals()</code> method. 233 * Sometimes, when extra flexibility is required then you might use argument matchers: 234 * 235 * <pre class="code"><code class="java"> 236 * //stubbing using built-in anyInt() argument matcher 237 * when(mockedList.get(anyInt())).thenReturn("element"); 238 * 239 * //stubbing using custom matcher (let's say isValid() returns your own matcher implementation): 240 * when(mockedList.contains(argThat(isValid()))).thenReturn("element"); 241 * 242 * //following prints "element" 243 * System.out.println(mockedList.get(999)); 244 * 245 * //<b>you can also verify using an argument matcher</b> 246 * verify(mockedList).get(anyInt()); 247 * 248 * //<b>argument matchers can also be written as Java 8 Lambdas</b> 249 * verify(mockedList).add(argThat(someString -> someString.length() > 5)); 250 * 251 * </code></pre> 252 * 253 * <p> 254 * Argument matchers allow flexible verification or stubbing. 255 * {@link ArgumentMatchers Click here} {@link org.mockito.hamcrest.MockitoHamcrest or here} to see more built-in matchers 256 * and examples of <b>custom argument matchers / hamcrest matchers</b>. 257 * <p> 258 * For information solely on <b>custom argument matchers</b> check out javadoc for {@link ArgumentMatcher} class. 259 * <p> 260 * Be reasonable with using complicated argument matching. 261 * The natural matching style using <code>equals()</code> with occasional <code>anyX()</code> matchers tend to give clean & simple tests. 262 * Sometimes it's just better to refactor the code to allow <code>equals()</code> matching or even implement <code>equals()</code> method to help out with testing. 263 * <p> 264 * Also, read <a href="#15">section 15</a> or javadoc for {@link ArgumentCaptor} class. 265 * {@link ArgumentCaptor} is a special implementation of an argument matcher that captures argument values for further assertions. 266 * <p> 267 * <b>Warning on argument matchers:</b> 268 * <p> 269 * If you are using argument matchers, <b>all arguments</b> have to be provided 270 * by matchers. 271 * <p> 272 The following example shows verification but the same applies to stubbing: 273 * 274 * <pre class="code"><code class="java"> 275 * verify(mock).someMethod(anyInt(), anyString(), <b>eq("third argument")</b>); 276 * //above is correct - eq() is also an argument matcher 277 * 278 * verify(mock).someMethod(anyInt(), anyString(), <b>"third argument"</b>); 279 * //above is incorrect - exception will be thrown because third argument is given without an argument matcher. 280 * </code></pre> 281 * 282 * <p> 283 * Matcher methods like <code>anyObject()</code>, <code>eq()</code> <b>do not</b> return matchers. 284 * Internally, they record a matcher on a stack and return a dummy value (usually null). 285 * This implementation is due to static type safety imposed by the java compiler. 286 * The consequence is that you cannot use <code>anyObject()</code>, <code>eq()</code> methods outside of verified/stubbed method. 287 * 288 * 289 * 290 * 291 * <h3 id="4">4. <a class="meaningful_link" href="#exact_verification" name="exact_verification">Verifying exact number of invocations</a> / 292 * <a class="meaningful_link" href="#at_least_verification" name="at_least_verification">at least x</a> / never</h3> 293 * 294 * <pre class="code"><code class="java"> 295 * //using mock 296 * mockedList.add("once"); 297 * 298 * mockedList.add("twice"); 299 * mockedList.add("twice"); 300 * 301 * mockedList.add("three times"); 302 * mockedList.add("three times"); 303 * mockedList.add("three times"); 304 * 305 * //following two verifications work exactly the same - times(1) is used by default 306 * verify(mockedList).add("once"); 307 * verify(mockedList, times(1)).add("once"); 308 * 309 * //exact number of invocations verification 310 * verify(mockedList, times(2)).add("twice"); 311 * verify(mockedList, times(3)).add("three times"); 312 * 313 * //verification using never(). never() is an alias to times(0) 314 * verify(mockedList, never()).add("never happened"); 315 * 316 * //verification using atLeast()/atMost() 317 * verify(mockedList, atLeastOnce()).add("three times"); 318 * verify(mockedList, atLeast(2)).add("three times"); 319 * verify(mockedList, atMost(5)).add("three times"); 320 * 321 * </code></pre> 322 * 323 * <p> 324 * <b>times(1) is the default.</b> Therefore using times(1) explicitly can be 325 * omitted. 326 * 327 * 328 * 329 * 330 * <h3 id="5">5. <a class="meaningful_link" href="#stubbing_with_exceptions" name="stubbing_with_exceptions">Stubbing void methods with exceptions</a></h3> 331 * 332 * <pre class="code"><code class="java"> 333 * doThrow(new RuntimeException()).when(mockedList).clear(); 334 * 335 * //following throws RuntimeException: 336 * mockedList.clear(); 337 * </code></pre> 338 * 339 * Read more about <code>doThrow()</code>|<code>doAnswer()</code> family of methods in <a href="#12">section 12</a>. 340 * <p> 341 * 342 * <h3 id="6">6. <a class="meaningful_link" href="#in_order_verification" name="in_order_verification">Verification in order</a></h3> 343 * 344 * <pre class="code"><code class="java"> 345 * // A. Single mock whose methods must be invoked in a particular order 346 * List singleMock = mock(List.class); 347 * 348 * //using a single mock 349 * singleMock.add("was added first"); 350 * singleMock.add("was added second"); 351 * 352 * //create an inOrder verifier for a single mock 353 * InOrder inOrder = inOrder(singleMock); 354 * 355 * //following will make sure that add is first called with "was added first, then with "was added second" 356 * inOrder.verify(singleMock).add("was added first"); 357 * inOrder.verify(singleMock).add("was added second"); 358 * 359 * // B. Multiple mocks that must be used in a particular order 360 * List firstMock = mock(List.class); 361 * List secondMock = mock(List.class); 362 * 363 * //using mocks 364 * firstMock.add("was called first"); 365 * secondMock.add("was called second"); 366 * 367 * //create inOrder object passing any mocks that need to be verified in order 368 * InOrder inOrder = inOrder(firstMock, secondMock); 369 * 370 * //following will make sure that firstMock was called before secondMock 371 * inOrder.verify(firstMock).add("was called first"); 372 * inOrder.verify(secondMock).add("was called second"); 373 * 374 * // Oh, and A + B can be mixed together at will 375 * </code></pre> 376 * 377 * Verification in order is flexible - <b>you don't have to verify all 378 * interactions</b> one-by-one but only those that you are interested in 379 * testing in order. 380 * <p> 381 * Also, you can create an InOrder object passing only the mocks that are relevant for 382 * in-order verification. 383 * 384 * 385 * 386 * 387 * <h3 id="7">7. <a class="meaningful_link" href="#never_verification" name="never_verification">Making sure interaction(s) never happened on mock</a></h3> 388 * 389 * <pre class="code"><code class="java"> 390 * //using mocks - only mockOne is interacted 391 * mockOne.add("one"); 392 * 393 * //ordinary verification 394 * verify(mockOne).add("one"); 395 * 396 * //verify that method was never called on a mock 397 * verify(mockOne, never()).add("two"); 398 * 399 * //verify that other mocks were not interacted 400 * verifyZeroInteractions(mockTwo, mockThree); 401 * 402 * </code></pre> 403 * 404 * 405 * 406 * 407 * <h3 id="8">8. <a class="meaningful_link" href="#finding_redundant_invocations" name="finding_redundant_invocations">Finding redundant invocations</a></h3> 408 * 409 * <pre class="code"><code class="java"> 410 * //using mocks 411 * mockedList.add("one"); 412 * mockedList.add("two"); 413 * 414 * verify(mockedList).add("one"); 415 * 416 * //following verification will fail 417 * verifyNoMoreInteractions(mockedList); 418 * </code></pre> 419 * 420 * A word of <b>warning</b>: 421 * Some users who did a lot of classic, expect-run-verify mocking tend to use <code>verifyNoMoreInteractions()</code> very often, even in every test method. 422 * <code>verifyNoMoreInteractions()</code> is not recommended to use in every test method. 423 * <code>verifyNoMoreInteractions()</code> is a handy assertion from the interaction testing toolkit. Use it only when it's relevant. 424 * Abusing it leads to <strong>overspecified</strong>, <strong>less maintainable</strong> tests. You can find further reading 425 * <a href="http://monkeyisland.pl/2008/07/12/should-i-worry-about-the-unexpected/">here</a>. 426 * 427 * <p> 428 * See also {@link Mockito#never()} - it is more explicit and 429 * communicates the intent well. 430 * <p> 431 * 432 * 433 * 434 * 435 * <h3 id="9">9. <a class="meaningful_link" href="#mock_annotation" name="mock_annotation">Shorthand for mocks creation - <code>@Mock</code> annotation</a></h3> 436 * 437 * <ul> 438 * <li>Minimizes repetitive mock creation code.</li> 439 * <li>Makes the test class more readable.</li> 440 * <li>Makes the verification error easier to read because the <b>field name</b> 441 * is used to identify the mock.</li> 442 * </ul> 443 * 444 * <pre class="code"><code class="java"> 445 * public class ArticleManagerTest { 446 * 447 * @Mock private ArticleCalculator calculator; 448 * @Mock private ArticleDatabase database; 449 * @Mock private UserProvider userProvider; 450 * 451 * private ArticleManager manager; 452 * </code></pre> 453 * 454 * <b>Important!</b> This needs to be somewhere in the base class or a test 455 * runner: 456 * 457 * <pre class="code"><code class="java"> 458 * MockitoAnnotations.initMocks(testClass); 459 * </code></pre> 460 * 461 * You can use built-in runner: {@link MockitoJUnitRunner} or a rule: {@link MockitoRule}. 462 * <p> 463 * Read more here: {@link MockitoAnnotations} 464 * 465 * 466 * 467 * 468 * <h3 id="10">10. <a class="meaningful_link" href="#stubbing_consecutive_calls" name="stubbing_consecutive_calls">Stubbing consecutive calls</a> (iterator-style stubbing)</h3> 469 * 470 * Sometimes we need to stub with different return value/exception for the same 471 * method call. Typical use case could be mocking iterators. 472 * Original version of Mockito did not have this feature to promote simple mocking. 473 * For example, instead of iterators one could use {@link Iterable} or simply 474 * collections. Those offer natural ways of stubbing (e.g. using real 475 * collections). In rare scenarios stubbing consecutive calls could be useful, 476 * though: 477 * <p> 478 * 479 * <pre class="code"><code class="java"> 480 * when(mock.someMethod("some arg")) 481 * .thenThrow(new RuntimeException()) 482 * .thenReturn("foo"); 483 * 484 * //First call: throws runtime exception: 485 * mock.someMethod("some arg"); 486 * 487 * //Second call: prints "foo" 488 * System.out.println(mock.someMethod("some arg")); 489 * 490 * //Any consecutive call: prints "foo" as well (last stubbing wins). 491 * System.out.println(mock.someMethod("some arg")); 492 * </code></pre> 493 * 494 * Alternative, shorter version of consecutive stubbing: 495 * 496 * <pre class="code"><code class="java"> 497 * when(mock.someMethod("some arg")) 498 * .thenReturn("one", "two", "three"); 499 * </code></pre> 500 * 501 * <strong>Warning</strong> : if instead of chaining {@code .thenReturn()} calls, multiple stubbing with the same matchers or arguments 502 * is used, then each stubbing will override the previous one: 503 * 504 * <pre class="code"><code class="java"> 505 * //All mock.someMethod("some arg") calls will return "two" 506 * when(mock.someMethod("some arg")) 507 * .thenReturn("one") 508 * when(mock.someMethod("some arg")) 509 * .thenReturn("two") 510 * </code></pre> 511 * 512 * 513 * 514 * <h3 id="11">11. <a class="meaningful_link" href="#answer_stubs" name="answer_stubs">Stubbing with callbacks</a></h3> 515 * 516 * Allows stubbing with generic {@link Answer} interface. 517 * <p> 518 * Yet another controversial feature which was not included in Mockito 519 * originally. We recommend simply stubbing with <code>thenReturn()</code> or 520 * <code>thenThrow()</code>, which should be enough to test/test-drive 521 * any clean & simple code. However, if you do have a need to stub with the generic Answer interface, here is an example: 522 * 523 * <pre class="code"><code class="java"> 524 * when(mock.someMethod(anyString())).thenAnswer(new Answer() { 525 * Object answer(InvocationOnMock invocation) { 526 * Object[] args = invocation.getArguments(); 527 * Object mock = invocation.getMock(); 528 * return "called with arguments: " + args; 529 * } 530 * }); 531 * 532 * //the following prints "called with arguments: foo" 533 * System.out.println(mock.someMethod("foo")); 534 * </code></pre> 535 * 536 * 537 * 538 * 539 * <h3 id="12">12. <a class="meaningful_link" href="#do_family_methods_stubs" name="do_family_methods_stubs"><code>doReturn()</code>|<code>doThrow()</code>| 540 * <code>doAnswer()</code>|<code>doNothing()</code>|<code>doCallRealMethod()</code> family of methods</a></h3> 541 * 542 * Stubbing void methods requires a different approach from {@link Mockito#when(Object)} because the compiler does not 543 * like void methods inside brackets... 544 * <p> 545 * Use <code>doThrow()</code> when you want to stub a void method with an exception: 546 * <pre class="code"><code class="java"> 547 * doThrow(new RuntimeException()).when(mockedList).clear(); 548 * 549 * //following throws RuntimeException: 550 * mockedList.clear(); 551 * </code></pre> 552 * </p> 553 * 554 * <p> 555 * You can use <code>doThrow()</code>, <code>doAnswer()</code>, <code>doNothing()</code>, <code>doReturn()</code> 556 * and <code>doCallRealMethod()</code> in place of the corresponding call with <code>when()</code>, for any method. 557 * It is necessary when you 558 * <ul> 559 * <li>stub void methods</li> 560 * <li>stub methods on spy objects (see below)</li> 561 * <li>stub the same method more than once, to change the behaviour of a mock in the middle of a test.</li> 562 * </ul> 563 * but you may prefer to use these methods in place of the alternative with <code>when()</code>, for all of your stubbing calls. 564 * <p> 565 * Read more about these methods: 566 * <p> 567 * {@link Mockito#doReturn(Object)} 568 * <p> 569 * {@link Mockito#doThrow(Throwable...)} 570 * <p> 571 * {@link Mockito#doThrow(Class)} 572 * <p> 573 * {@link Mockito#doAnswer(Answer)} 574 * <p> 575 * {@link Mockito#doNothing()} 576 * <p> 577 * {@link Mockito#doCallRealMethod()} 578 * 579 * 580 * 581 * 582 * <h3 id="13">13. <a class="meaningful_link" href="#spy" name="spy">Spying on real objects</a></h3> 583 * 584 * You can create spies of real objects. When you use the spy then the <b>real</b> methods are called 585 * (unless a method was stubbed). 586 * <p> 587 * Real spies should be used <b>carefully and occasionally</b>, for example when dealing with legacy code. 588 * 589 * <p> 590 * Spying on real objects can be associated with "partial mocking" concept. 591 * <b>Before the release 1.8</b>, Mockito spies were not real partial mocks. 592 * The reason was we thought partial mock is a code smell. 593 * At some point we found legitimate use cases for partial mocks 594 * (3rd party interfaces, interim refactoring of legacy code, the full article is 595 * <a href="http://monkeyisland.pl/2009/01/13/subclass-and-override-vs-partial-mocking-vs-refactoring">here</a>) 596 * <p> 597 * 598 * <pre class="code"><code class="java"> 599 * List list = new LinkedList(); 600 * List spy = spy(list); 601 * 602 * //optionally, you can stub out some methods: 603 * when(spy.size()).thenReturn(100); 604 * 605 * //using the spy calls <b>*real*</b> methods 606 * spy.add("one"); 607 * spy.add("two"); 608 * 609 * //prints "one" - the first element of a list 610 * System.out.println(spy.get(0)); 611 * 612 * //size() method was stubbed - 100 is printed 613 * System.out.println(spy.size()); 614 * 615 * //optionally, you can verify 616 * verify(spy).add("one"); 617 * verify(spy).add("two"); 618 * </code></pre> 619 * 620 * <h4>Important gotcha on spying real objects!</h4> 621 * <ol> 622 * <li>Sometimes it's impossible or impractical to use {@link Mockito#when(Object)} for stubbing spies. 623 * Therefore when using spies please consider <code>doReturn</code>|<code>Answer</code>|<code>Throw()</code> family of 624 * methods for stubbing. Example: 625 * 626 * <pre class="code"><code class="java"> 627 * List list = new LinkedList(); 628 * List spy = spy(list); 629 * 630 * //Impossible: real method is called so spy.get(0) throws IndexOutOfBoundsException (the list is yet empty) 631 * when(spy.get(0)).thenReturn("foo"); 632 * 633 * //You have to use doReturn() for stubbing 634 * doReturn("foo").when(spy).get(0); 635 * </code></pre> 636 * </li> 637 * 638 * <li>Mockito <b>*does not*</b> delegate calls to the passed real instance, instead it actually creates a copy of it. 639 * So if you keep the real instance and interact with it, don't expect the spied to be aware of those interaction 640 * and their effect on real instance state. 641 * The corollary is that when an <b>*unstubbed*</b> method is called <b>*on the spy*</b> but <b>*not on the real instance*</b>, 642 * you won't see any effects on the real instance. 643 * </li> 644 * 645 * <li>Watch out for final methods. 646 * Mockito doesn't mock final methods so the bottom line is: when you spy on real objects + you try to stub a final method = trouble. 647 * Also you won't be able to verify those method as well. 648 * </li> 649 * </ol> 650 * 651 * 652 * 653 * 654 * <h3 id="14">14. Changing <a class="meaningful_link" href="#defaultreturn" name="defaultreturn">default return values of unstubbed invocations</a> (Since 1.7)</h3> 655 * 656 * You can create a mock with specified strategy for its return values. 657 * It's quite an advanced feature and typically you don't need it to write decent tests. 658 * However, it can be helpful for working with <b>legacy systems</b>. 659 * <p> 660 * It is the default answer so it will be used <b>only when you don't</b> stub the method call. 661 * 662 * <pre class="code"><code class="java"> 663 * Foo mock = mock(Foo.class, Mockito.RETURNS_SMART_NULLS); 664 * Foo mockTwo = mock(Foo.class, new YourOwnAnswer()); 665 * </code></pre> 666 * 667 * <p> 668 * Read more about this interesting implementation of <i>Answer</i>: {@link Mockito#RETURNS_SMART_NULLS} 669 * 670 * 671 * 672 * 673 * <h3 id="15">15. <a class="meaningful_link" href="#captors" name="captors">Capturing arguments</a> for further assertions (Since 1.8.0)</h3> 674 * 675 * Mockito verifies argument values in natural java style: by using an <code>equals()</code> method. 676 * This is also the recommended way of matching arguments because it makes tests clean & simple. 677 * In some situations though, it is helpful to assert on certain arguments after the actual verification. 678 * For example: 679 * <pre class="code"><code class="java"> 680 * ArgumentCaptor<Person> argument = ArgumentCaptor.forClass(Person.class); 681 * verify(mock).doSomething(argument.capture()); 682 * assertEquals("John", argument.getValue().getName()); 683 * </code></pre> 684 * 685 * <b>Warning:</b> it is recommended to use ArgumentCaptor with verification <b>but not</b> with stubbing. 686 * Using ArgumentCaptor with stubbing may decrease test readability because captor is created outside of assert (aka verify or 'then') block. 687 * Also it may reduce defect localization because if stubbed method was not called then no argument is captured. 688 * <p> 689 * In a way ArgumentCaptor is related to custom argument matchers (see javadoc for {@link ArgumentMatcher} class). 690 * Both techniques can be used for making sure certain arguments where passed to mocks. 691 * However, ArgumentCaptor may be a better fit if: 692 * <ul> 693 * <li>custom argument matcher is not likely to be reused</li> 694 * <li>you just need it to assert on argument values to complete verification</li> 695 * </ul> 696 * Custom argument matchers via {@link ArgumentMatcher} are usually better for stubbing. 697 * 698 * 699 * 700 * 701 * <h3 id="16">16. <a class="meaningful_link" href="#partial_mocks" name="partial_mocks">Real partial mocks</a> (Since 1.8.0)</h3> 702 * 703 * Finally, after many internal debates & discussions on the mailing list, partial mock support was added to Mockito. 704 * Previously we considered partial mocks as code smells. However, we found a legitimate use case for partial mocks - more reading: 705 * <a href="http://monkeyisland.pl/2009/01/13/subclass-and-override-vs-partial-mocking-vs-refactoring">here</a> 706 * <p> 707 * <b>Before release 1.8</b> <code>spy()</code> was not producing real partial mocks and it was confusing for some users. 708 * Read more about spying: <a href="#13">here</a> or in javadoc for {@link Mockito#spy(Object)} method. 709 * <p> 710 * <pre class="code"><code class="java"> 711 * //you can create partial mock with spy() method: 712 * List list = spy(new LinkedList()); 713 * 714 * //you can enable partial mock capabilities selectively on mocks: 715 * Foo mock = mock(Foo.class); 716 * //Be sure the real implementation is 'safe'. 717 * //If real implementation throws exceptions or depends on specific state of the object then you're in trouble. 718 * when(mock.someMethod()).thenCallRealMethod(); 719 * </code></pre> 720 * 721 * As usual you are going to read <b>the partial mock warning</b>: 722 * Object oriented programming is more less tackling complexity by dividing the complexity into separate, specific, SRPy objects. 723 * How does partial mock fit into this paradigm? Well, it just doesn't... 724 * Partial mock usually means that the complexity has been moved to a different method on the same object. 725 * In most cases, this is not the way you want to design your application. 726 * <p> 727 * However, there are rare cases when partial mocks come handy: 728 * dealing with code you cannot change easily (3rd party interfaces, interim refactoring of legacy code etc.) 729 * However, I wouldn't use partial mocks for new, test-driven & well-designed code. 730 * 731 * 732 * 733 * 734 * <h3 id="17">17. <a class="meaningful_link" href="#resetting_mocks" name="resetting_mocks">Resetting mocks</a> (Since 1.8.0)</h3> 735 * 736 * Smart Mockito users hardly use this feature because they know it could be a sign of poor tests. 737 * Normally, you don't need to reset your mocks, just create new mocks for each test method. 738 * <p> 739 * Instead of <code>reset()</code> please consider writing simple, small and focused test methods over lengthy, over-specified tests. 740 * <b>First potential code smell is <code>reset()</code> in the middle of the test method.</b> This probably means you're testing too much. 741 * Follow the whisper of your test methods: "Please keep us small & focused on single behavior". 742 * There are several threads about it on mockito mailing list. 743 * <p> 744 * The only reason we added <code>reset()</code> method is to 745 * make it possible to work with container-injected mocks. 746 * For more information see FAQ (<a href="https://github.com/mockito/mockito/wiki/FAQ">here</a>). 747 * <p> 748 * <b>Don't harm yourself.</b> <code>reset()</code> in the middle of the test method is a code smell (you're probably testing too much). 749 * <pre class="code"><code class="java"> 750 * List mock = mock(List.class); 751 * when(mock.size()).thenReturn(10); 752 * mock.add(1); 753 * 754 * reset(mock); 755 * //at this point the mock forgot any interactions & stubbing 756 * </code></pre> 757 * 758 * 759 * 760 * 761 * <h3 id="18">18. <a class="meaningful_link" href="#framework_validation" name="framework_validation">Troubleshooting & validating framework usage</a> (Since 1.8.0)</h3> 762 * 763 * First of all, in case of any trouble, I encourage you to read the Mockito FAQ: 764 * <a href="https://github.com/mockito/mockito/wiki/FAQ">https://github.com/mockito/mockito/wiki/FAQ</a> 765 * <p> 766 * In case of questions you may also post to mockito mailing list: 767 * <a href="http://groups.google.com/group/mockito">http://groups.google.com/group/mockito</a> 768 * <p> 769 * Next, you should know that Mockito validates if you use it correctly <b>all the time</b>. 770 * However, there's a gotcha so please read the javadoc for {@link Mockito#validateMockitoUsage()} 771 * 772 * 773 * 774 * 775 * <h3 id="19">19. <a class="meaningful_link" href="#bdd_mockito" name="bdd_mockito">Aliases for behavior driven development</a> (Since 1.8.0)</h3> 776 * 777 * Behavior Driven Development style of writing tests uses <b>//given //when //then</b> comments as fundamental parts of your test methods. 778 * This is exactly how we write our tests and we warmly encourage you to do so! 779 * <p> 780 * Start learning about BDD here: <a href="http://en.wikipedia.org/wiki/Behavior_Driven_Development">http://en.wikipedia.org/wiki/Behavior_Driven_Development</a> 781 * <p> 782 * The problem is that current stubbing api with canonical role of <b>when</b> word does not integrate nicely with <b>//given //when //then</b> comments. 783 * It's because stubbing belongs to <b>given</b> component of the test and not to the <b>when</b> component of the test. 784 * Hence {@link BDDMockito} class introduces an alias so that you stub method calls with {@link BDDMockito#given(Object)} method. 785 * Now it really nicely integrates with the <b>given</b> component of a BDD style test! 786 * <p> 787 * Here is how the test might look like: 788 * <pre class="code"><code class="java"> 789 * import static org.mockito.BDDMockito.*; 790 * 791 * Seller seller = mock(Seller.class); 792 * Shop shop = new Shop(seller); 793 * 794 * public void shouldBuyBread() throws Exception { 795 * //given 796 * given(seller.askForBread()).willReturn(new Bread()); 797 * 798 * //when 799 * Goods goods = shop.buyBread(); 800 * 801 * //then 802 * assertThat(goods, containBread()); 803 * } 804 * </code></pre> 805 * 806 * 807 * 808 * 809 * <h3 id="20">20. <a class="meaningful_link" href="#serializable_mocks" name="serializable_mocks">Serializable mocks</a> (Since 1.8.1)</h3> 810 * 811 * Mocks can be made serializable. With this feature you can use a mock in a place that requires dependencies to be serializable. 812 * <p> 813 * WARNING: This should be rarely used in unit testing. 814 * <p> 815 * The behaviour was implemented for a specific use case of a BDD spec that had an unreliable external dependency. This 816 * was in a web environment and the objects from the external dependency were being serialized to pass between layers. 817 * <p> 818 * To create serializable mock use {@link MockSettings#serializable()}: 819 * <pre class="code"><code class="java"> 820 * List serializableMock = mock(List.class, withSettings().serializable()); 821 * </code></pre> 822 * <p> 823 * The mock can be serialized assuming all the normal <a href='http://java.sun.com/j2se/1.5.0/docs/api/java/io/Serializable.html'> 824 * serialization requirements</a> are met by the class. 825 * <p> 826 * Making a real object spy serializable is a bit more effort as the spy(...) method does not have an overloaded version 827 * which accepts MockSettings. No worries, you will hardly ever use it. 828 * 829 * <pre class="code"><code class="java"> 830 * List<Object> list = new ArrayList<Object>(); 831 * List<Object> spy = mock(ArrayList.class, withSettings() 832 * .spiedInstance(list) 833 * .defaultAnswer(CALLS_REAL_METHODS) 834 * .serializable()); 835 * </code></pre> 836 * 837 * 838 * 839 * 840 * <h3 id="21">21. New annotations: <a class="meaningful_link" href="#captor_annotation" name="captor_annotation"><code>@Captor</code></a>, 841 * <a class="meaningful_link" href="#spy_annotation" name="spy_annotation"><code>@Spy</code></a>, 842 * <a class="meaningful_link" href="#injectmocks_annotation" name="injectmocks_annotation"><code>@InjectMocks</code></a> (Since 1.8.3)</h3> 843 * 844 * <p> 845 * Release 1.8.3 brings new annotations that may be helpful on occasion: 846 * 847 * <ul> 848 * <li>@{@link Captor} simplifies creation of {@link ArgumentCaptor} 849 * - useful when the argument to capture is a nasty generic class and you want to avoid compiler warnings 850 * <li>@{@link Spy} - you can use it instead {@link Mockito#spy(Object)}. 851 * <li>@{@link InjectMocks} - injects mock or spy fields into tested object automatically. 852 * </ul> 853 * 854 * <p> 855 * Note that @{@link InjectMocks} can also be used in combination with the @{@link Spy} annotation, it means 856 * that Mockito will inject mocks into the partial mock under test. This complexity is another good reason why you 857 * should only use partial mocks as a last resort. See point 16 about partial mocks. 858 * 859 * <p> 860 * All new annotations are <b>*only*</b> processed on {@link MockitoAnnotations#initMocks(Object)}. 861 * Just like for @{@link Mock} annotation you can use the built-in runner: {@link MockitoJUnitRunner} or rule: 862 * {@link MockitoRule}. 863 * <p> 864 * 865 * 866 * 867 * 868 * <h3 id="22">22. <a class="meaningful_link" href="#verification_timeout" name="verification_timeout">Verification with timeout</a> (Since 1.8.5)</h3> 869 * <p> 870 * Allows verifying with timeout. It causes a verify to wait for a specified period of time for a desired 871 * interaction rather than fails immediately if had not already happened. May be useful for testing in concurrent 872 * conditions. 873 * <p> 874 * This feature should be used rarely - figure out a better way of testing your multi-threaded system. 875 * <p> 876 * Not yet implemented to work with InOrder verification. 877 * <p> 878 * Examples: 879 * <p> 880 * <pre class="code"><code class="java"> 881 * //passes when someMethod() is called within given time span 882 * verify(mock, timeout(100)).someMethod(); 883 * //above is an alias to: 884 * verify(mock, timeout(100).times(1)).someMethod(); 885 * 886 * //passes when someMethod() is called <b>*exactly*</b> 2 times within given time span 887 * verify(mock, timeout(100).times(2)).someMethod(); 888 * 889 * //passes when someMethod() is called <b>*at least*</b> 2 times within given time span 890 * verify(mock, timeout(100).atLeast(2)).someMethod(); 891 * 892 * //verifies someMethod() within given time span using given verification mode 893 * //useful only if you have your own custom verification modes. 894 * verify(mock, new Timeout(100, yourOwnVerificationMode)).someMethod(); 895 * </code></pre> 896 * 897 * 898 * 899 * 900 * <h3 id="23">23. <a class="meaningful_link" href="#automatic_instantiation" name="automatic_instantiation">Automatic instantiation of <code>@Spies</code>, 901 * <code>@InjectMocks</code></a> and <a class="meaningful_link" href="#constructor_injection" name="constructor_injection">constructor injection goodness</a> (Since 1.9.0)</h3> 902 * 903 * <p> 904 * Mockito will now try to instantiate @{@link Spy} and will instantiate @{@link InjectMocks} fields 905 * using <b>constructor</b> injection, <b>setter</b> injection, or <b>field</b> injection. 906 * <p> 907 * To take advantage of this feature you need to use {@link MockitoAnnotations#initMocks(Object)}, {@link MockitoJUnitRunner} 908 * or {@link MockitoRule}. 909 * <p> 910 * Read more about available tricks and the rules of injection in the javadoc for {@link InjectMocks} 911 * <pre class="code"><code class="java"> 912 * //instead: 913 * @Spy BeerDrinker drinker = new BeerDrinker(); 914 * //you can write: 915 * @Spy BeerDrinker drinker; 916 * 917 * //same applies to @InjectMocks annotation: 918 * @InjectMocks LocalPub; 919 * </code></pre> 920 * 921 * 922 * 923 * 924 * <h3 id="24">24. <a class="meaningful_link" href="#one_liner_stub" name="one_liner_stub">One-liner stubs</a> (Since 1.9.0)</h3> 925 * <p> 926 * Mockito will now allow you to create mocks when stubbing. 927 * Basically, it allows to create a stub in one line of code. 928 * This can be helpful to keep test code clean. 929 * For example, some boring stub can be created & stubbed at field initialization in a test: 930 * <pre class="code"><code class="java"> 931 * public class CarTest { 932 * Car boringStubbedCar = when(mock(Car.class).shiftGear()).thenThrow(EngineNotStarted.class).getMock(); 933 * 934 * @Test public void should... {} 935 * </code></pre> 936 * 937 * 938 * 939 * 940 * <h3 id="25">25. <a class="meaningful_link" href="#ignore_stubs_verification" name="ignore_stubs_verification">Verification ignoring stubs</a> (Since 1.9.0)</h3> 941 * <p> 942 * Mockito will now allow to ignore stubbing for the sake of verification. 943 * Sometimes useful when coupled with <code>verifyNoMoreInteractions()</code> or verification <code>inOrder()</code>. 944 * Helps avoiding redundant verification of stubbed calls - typically we're not interested in verifying stubs. 945 * <p> 946 * <b>Warning</b>, <code>ignoreStubs()</code> might lead to overuse of verifyNoMoreInteractions(ignoreStubs(...)); 947 * Bear in mind that Mockito does not recommend bombarding every test with <code>verifyNoMoreInteractions()</code> 948 * for the reasons outlined in javadoc for {@link Mockito#verifyNoMoreInteractions(Object...)} 949 * <p>Some examples: 950 * <pre class="code"><code class="java"> 951 * verify(mock).foo(); 952 * verify(mockTwo).bar(); 953 * 954 * //ignores all stubbed methods: 955 * verifyNoMoreInteractions(ignoreStubs(mock, mockTwo)); 956 * 957 * //creates InOrder that will ignore stubbed 958 * InOrder inOrder = inOrder(ignoreStubs(mock, mockTwo)); 959 * inOrder.verify(mock).foo(); 960 * inOrder.verify(mockTwo).bar(); 961 * inOrder.verifyNoMoreInteractions(); 962 * </code></pre> 963 * <p> 964 * Advanced examples and more details can be found in javadoc for {@link Mockito#ignoreStubs(Object...)} 965 * 966 * 967 * 968 * 969 * <h3 id="26">26. <a class="meaningful_link" href="#mocking_details" name="mocking_details">Mocking details</a> (Improved in 2.2.x)</h3> 970 * <p> 971 * 972 * Mockito offers API to inspect the details of a mock object. 973 * This API is useful for advanced users and mocking framework integrators. 974 * 975 * <pre class="code"><code class="java"> 976 * //To identify whether a particular object is a mock or a spy: 977 * Mockito.mockingDetails(someObject).isMock(); 978 * Mockito.mockingDetails(someObject).isSpy(); 979 * 980 * //Getting details like type to mock or default answer: 981 * MockingDetails details = mockingDetails(mock); 982 * details.getMockCreationSettings().getTypeToMock(); 983 * details.getMockCreationSettings().getDefaultAnswer(); 984 * 985 * //Getting interactions and stubbings of the mock: 986 * MockingDetails details = mockingDetails(mock); 987 * details.getInteractions(); 988 * details.getStubbings(); 989 * 990 * //Printing all interactions (including stubbing, unused stubs) 991 * System.out.println(mockingDetails(mock).printInvocations()); 992 * </code></pre> 993 * 994 * For more information see javadoc for {@link MockingDetails}. 995 * 996 * <h3 id="27">27. <a class="meaningful_link" href="#delegating_call_to_real_instance" name="delegating_call_to_real_instance">Delegate calls to real instance</a> (Since 1.9.5)</h3> 997 * 998 * <p>Useful for spies or partial mocks of objects <strong>that are difficult to mock or spy</strong> using the usual spy API. 999 * Since Mockito 1.10.11, the delegate may or may not be of the same type as the mock. 1000 * If the type is different, a matching method needs to be found on delegate type otherwise an exception is thrown. 1001 * 1002 * Possible use cases for this feature: 1003 * <ul> 1004 * <li>Final classes but with an interface</li> 1005 * <li>Already custom proxied object</li> 1006 * <li>Special objects with a finalize method, i.e. to avoid executing it 2 times</li> 1007 * </ul> 1008 * 1009 * <p>The difference with the regular spy: 1010 * <ul> 1011 * <li> 1012 * The regular spy ({@link #spy(Object)}) contains <strong>all</strong> state from the spied instance 1013 * and the methods are invoked on the spy. The spied instance is only used at mock creation to copy the state from. 1014 * If you call a method on a regular spy and it internally calls other methods on this spy, those calls are remembered 1015 * for verifications, and they can be effectively stubbed. 1016 * </li> 1017 * <li> 1018 * The mock that delegates simply delegates all methods to the delegate. 1019 * The delegate is used all the time as methods are delegated onto it. 1020 * If you call a method on a mock that delegates and it internally calls other methods on this mock, 1021 * those calls are <strong>not</strong> remembered for verifications, stubbing does not have effect on them, too. 1022 * Mock that delegates is less powerful than the regular spy but it is useful when the regular spy cannot be created. 1023 * </li> 1024 * </ul> 1025 * 1026 * <p> 1027 * See more information in docs for {@link AdditionalAnswers#delegatesTo(Object)}. 1028 * 1029 * 1030 * 1031 * 1032 * <h3 id="28">28. <a class="meaningful_link" href="#mock_maker_plugin" name="mock_maker_plugin"><code>MockMaker</code> API</a> (Since 1.9.5)</h3> 1033 * <p>Driven by requirements and patches from Google Android guys Mockito now offers an extension point 1034 * that allows replacing the proxy generation engine. By default, Mockito uses <a href="https://github.com/raphw/byte-buddy">Byte Buddy</a> 1035 * to create dynamic proxies. 1036 * <p>The extension point is for advanced users that want to extend Mockito. For example, it is now possible 1037 * to use Mockito for Android testing with a help of <a href="https://github.com/crittercism/dexmaker">dexmaker</a>. 1038 * <p>For more details, motivations and examples please refer to 1039 * the docs for {@link org.mockito.plugins.MockMaker}. 1040 * 1041 * 1042 * 1043 * 1044 * <h3 id="29">29. <a class="meaningful_link" href="#BDD_behavior_verification" name="BDD_behavior_verification">BDD style verification</a> (Since 1.10.0)</h3> 1045 * 1046 * Enables Behavior Driven Development (BDD) style verification by starting verification with the BDD <b>then</b> keyword. 1047 * 1048 * <pre class="code"><code class="java"> 1049 * given(dog.bark()).willReturn(2); 1050 * 1051 * // when 1052 * ... 1053 * 1054 * then(person).should(times(2)).ride(bike); 1055 * </code></pre> 1056 * 1057 * For more information and an example see {@link BDDMockito#then(Object)}} 1058 * 1059 * 1060 * 1061 * 1062 * <h3 id="30">30. <a class="meaningful_link" href="#spying_abstract_classes" name="spying_abstract_classes">Spying or mocking abstract classes (Since 1.10.12, further enhanced in 2.7.13 and 2.7.14)</a></h3> 1063 * 1064 * It is now possible to conveniently spy on abstract classes. Note that overusing spies hints at code design smells (see {@link #spy(Object)}). 1065 * <p> 1066 * Previously, spying was only possible on instances of objects. 1067 * New API makes it possible to use constructor when creating an instance of the mock. 1068 * This is particularly useful for mocking abstract classes because the user is no longer required to provide an instance of the abstract class. 1069 * At the moment, only parameter-less constructor is supported, let us know if it is not enough. 1070 * 1071 * <pre class="code"><code class="java"> 1072 * //convenience API, new overloaded spy() method: 1073 * SomeAbstract spy = spy(SomeAbstract.class); 1074 * 1075 * //Mocking abstract methods, spying default methods of an interface (only available since 2.7.13) 1076 * Function<Foo, Bar> function = spy(Function.class); 1077 * 1078 * //Robust API, via settings builder: 1079 * OtherAbstract spy = mock(OtherAbstract.class, withSettings() 1080 * .useConstructor().defaultAnswer(CALLS_REAL_METHODS)); 1081 * 1082 * //Mocking an abstract class with constructor arguments (only available since 2.7.14) 1083 * SomeAbstract spy = mock(SomeAbstract.class, withSettings() 1084 * .useConstructor("arg1", 123).defaultAnswer(CALLS_REAL_METHODS)); 1085 * 1086 * //Mocking a non-static inner abstract class: 1087 * InnerAbstract spy = mock(InnerAbstract.class, withSettings() 1088 * .useConstructor().outerInstance(outerInstance).defaultAnswer(CALLS_REAL_METHODS)); 1089 * </code></pre> 1090 * 1091 * For more information please see {@link MockSettings#useConstructor(Object...)}. 1092 * 1093 * 1094 * 1095 * 1096 * <h3 id="31">31. <a class="meaningful_link" href="#serilization_across_classloader" name="serilization_across_classloader">Mockito mocks can be <em>serialized</em> / <em>deserialized</em> across classloaders (Since 1.10.0)</a></h3> 1097 * 1098 * Mockito introduces serialization across classloader. 1099 * 1100 * Like with any other form of serialization, all types in the mock hierarchy have to serializable, inclusing answers. 1101 * As this serialization mode require considerably more work, this is an opt-in setting. 1102 * 1103 * <pre class="code"><code class="java"> 1104 * // use regular serialization 1105 * mock(Book.class, withSettings().serializable()); 1106 * 1107 * // use serialization across classloaders 1108 * mock(Book.class, withSettings().serializable(ACROSS_CLASSLOADERS)); 1109 * </code></pre> 1110 * 1111 * For more details see {@link MockSettings#serializable(SerializableMode)}. 1112 * 1113 * 1114 * 1115 * 1116 * <h3 id="32">32. <a class="meaningful_link" href="#better_generic_support_with_deep_stubs" name="better_generic_support_with_deep_stubs">Better generic support with deep stubs (Since 1.10.0)</a></h3> 1117 * 1118 * Deep stubbing has been improved to find generic information if available in the class. 1119 * That means that classes like this can be used without having to mock the behavior. 1120 * 1121 * <pre class="code"><code class="java"> 1122 * class Lines extends List<Line> { 1123 * // ... 1124 * } 1125 * 1126 * lines = mock(Lines.class, RETURNS_DEEP_STUBS); 1127 * 1128 * // Now Mockito understand this is not an Object but a Line 1129 * Line line = lines.iterator().next(); 1130 * </code></pre> 1131 * 1132 * Please note that in most scenarios a mock returning a mock is wrong. 1133 * 1134 * 1135 * 1136 * 1137 * <h3 id="33">33. <a class="meaningful_link" href="#mockito_junit_rule" name="mockito_junit_rule">Mockito JUnit rule (Since 1.10.17)</a></h3> 1138 * 1139 * Mockito now offers a JUnit rule. Until now in JUnit there were two ways to initialize fields annotated by Mockito annotations 1140 * such as <code>@{@link Mock}</code>, <code>@{@link Spy}</code>, <code>@{@link InjectMocks}</code>, etc. 1141 * 1142 * <ul> 1143 * <li>Annotating the JUnit test class with a <code>@{@link org.junit.runner.RunWith}({@link MockitoJUnitRunner}.class)</code></li> 1144 * <li>Invoking <code>{@link MockitoAnnotations#initMocks(Object)}</code> in the <code>@{@link org.junit.Before}</code> method</li> 1145 * </ul> 1146 * 1147 * Now you can choose to use a rule : 1148 * 1149 * <pre class="code"><code class="java"> 1150 * @RunWith(YetAnotherRunner.class) 1151 * public class TheTest { 1152 * @Rule public MockitoRule mockito = MockitoJUnit.rule(); 1153 * // ... 1154 * } 1155 * </code></pre> 1156 * 1157 * For more information see {@link MockitoJUnit#rule()}. 1158 * 1159 * 1160 * 1161 * 1162 * <h3 id="34">34. <a class="meaningful_link" href="#plugin_switch" name="plugin_switch">Switch <em>on</em> or <em>off</em> plugins (Since 1.10.15)</a></h3> 1163 * 1164 * An incubating feature made it's way in mockito that will allow to toggle a mockito-plugin. 1165 * 1166 * More information here {@link org.mockito.plugins.PluginSwitch}. 1167 * 1168 * 1169 * <h3 id="35">35. <a class="meaningful_link" href="#BDD_behavior_verification" name="BDD_behavior_verification">Custom verification failure message</a> (Since 2.1.0)</h3> 1170 * <p> 1171 * Allows specifying a custom message to be printed if verification fails. 1172 * <p> 1173 * Examples: 1174 * <p> 1175 * <pre class="code"><code class="java"> 1176 * 1177 * // will print a custom message on verification failure 1178 * verify(mock, description("This will print on failure")).someMethod(); 1179 * 1180 * // will work with any verification mode 1181 * verify(mock, times(2).description("someMethod should be called twice")).someMethod(); 1182 * </code></pre> 1183 * 1184 * <h3 id="36">36. <a class="meaningful_link" href="#Java_8_Lambda_Matching" name="Java_8_Lambda_Matching">Java 8 Lambda Matcher Support</a> (Since 2.1.0)</h3> 1185 * <p> 1186 * You can use Java 8 lambda expressions with {@link ArgumentMatcher} to reduce the dependency on {@link ArgumentCaptor}. 1187 * If you need to verify that the input to a function call on a mock was correct, then you would normally 1188 * use the {@link ArgumentCaptor} to find the operands used and then do subsequent assertions on them. While 1189 * for complex examples this can be useful, it's also long-winded.<p> 1190 * Writing a lambda to express the match is quite easy. The argument to your function, when used in conjunction 1191 * with argThat, will be passed to the ArgumentMatcher as a strongly typed object, so it is possible 1192 * to do anything with it. 1193 * <p> 1194 * Examples: 1195 * <p> 1196 * <pre class="code"><code class="java"> 1197 * 1198 * // verify a list only had strings of a certain length added to it 1199 * // note - this will only compile under Java 8 1200 * verify(list, times(2)).add(argThat(string -> string.length() < 5)); 1201 * 1202 * // Java 7 equivalent - not as neat 1203 * verify(list, times(2)).add(argThat(new ArgumentMatcher<String>(){ 1204 * public boolean matches(String arg) { 1205 * return arg.length() < 5; 1206 * } 1207 * })); 1208 * 1209 * // more complex Java 8 example - where you can specify complex verification behaviour functionally 1210 * verify(target, times(1)).receiveComplexObject(argThat(obj -> obj.getSubObject().get(0).equals("expected"))); 1211 * 1212 * // this can also be used when defining the behaviour of a mock under different inputs 1213 * // in this case if the input list was fewer than 3 items the mock returns null 1214 * when(mock.someMethod(argThat(list -> list.size()<3))).willReturn(null); 1215 * </code></pre> 1216 * 1217 * <h3 id="37">37. <a class="meaningful_link" href="#Java_8_Custom_Answers" name="Java_8_Custom_Answers">Java 8 Custom Answer Support</a> (Since 2.1.0)</h3> 1218 * <p> 1219 * As the {@link Answer} interface has just one method it is already possible to implement it in Java 8 using 1220 * a lambda expression for very simple situations. The more you need to use the parameters of the method call, 1221 * the more you need to typecast the arguments from {@link org.mockito.invocation.InvocationOnMock}. 1222 * 1223 * <p> 1224 * Examples: 1225 * <p> 1226 * <pre class="code"><code class="java"> 1227 * // answer by returning 12 every time 1228 * doAnswer(invocation -> 12).when(mock).doSomething(); 1229 * 1230 * // answer by using one of the parameters - converting into the right 1231 * // type as your go - in this case, returning the length of the second string parameter 1232 * // as the answer. This gets long-winded quickly, with casting of parameters. 1233 * doAnswer(invocation -> ((String)invocation.getArgument(1)).length()) 1234 * .when(mock).doSomething(anyString(), anyString(), anyString()); 1235 * </code></pre> 1236 * 1237 * For convenience it is possible to write custom answers/actions, which use the parameters to the method call, 1238 * as Java 8 lambdas. Even in Java 7 and lower these custom answers based on a typed interface can reduce boilerplate. 1239 * In particular, this approach will make it easier to test functions which use callbacks. 1240 * 1241 * The methods {@link AdditionalAnswers#answer(Answer1) answer} and {@link AdditionalAnswers#answerVoid(VoidAnswer1) answerVoid} 1242 * can be used to create the answer. They rely on the related answer interfaces in {@link org.mockito.stubbing} that 1243 * support answers up to 5 parameters. 1244 * 1245 * <p> 1246 * Examples: 1247 * <p> 1248 * <pre class="code"><code class="java"> 1249 * 1250 * // Example interface to be mocked has a function like: 1251 * void execute(String operand, Callback callback); 1252 * 1253 * // the example callback has a function and the class under test 1254 * // will depend on the callback being invoked 1255 * void receive(String item); 1256 * 1257 * // Java 8 - style 1 1258 * doAnswer(AdditionalAnswers.<String,Callback>answerVoid((operand, callback) -> callback.receive("dummy")) 1259 * .when(mock).execute(anyString(), any(Callback.class)); 1260 * 1261 * // Java 8 - style 2 - assuming static import of AdditionalAnswers 1262 * doAnswer(answerVoid((String operand, Callback callback) -> callback.receive("dummy")) 1263 * .when(mock).execute(anyString(), any(Callback.class)); 1264 * 1265 * // Java 8 - style 3 - where mocking function to is a static member of test class 1266 * private static void dummyCallbackImpl(String operation, Callback callback) { 1267 * callback.receive("dummy"); 1268 * } 1269 * 1270 * doAnswer(answerVoid(TestClass::dummyCallbackImpl) 1271 * .when(mock).execute(anyString(), any(Callback.class)); 1272 * 1273 * // Java 7 1274 * doAnswer(answerVoid(new VoidAnswer2<String, Callback>() { 1275 * public void answer(String operation, Callback callback) { 1276 * callback.receive("dummy"); 1277 * }})).when(mock).execute(anyString(), any(Callback.class)); 1278 * 1279 * // returning a value is possible with the answer() function 1280 * // and the non-void version of the functional interfaces 1281 * // so if the mock interface had a method like 1282 * boolean isSameString(String input1, String input2); 1283 * 1284 * // this could be mocked 1285 * // Java 8 1286 * doAnswer(AdditionalAnswers.<Boolean,String,String>answer((input1, input2) -> input1.equals(input2)))) 1287 * .when(mock).execute(anyString(), anyString()); 1288 * 1289 * // Java 7 1290 * doAnswer(answer(new Answer2<String, String, String>() { 1291 * public String answer(String input1, String input2) { 1292 * return input1 + input2; 1293 * }})).when(mock).execute(anyString(), anyString()); 1294 * </code></pre> 1295 * 1296 * <h3 id="38">38. <a class="meaningful_link" href="#Meta_Data_And_Generics" name="Meta_Data_And_Generics">Meta data and generic type retention</a> (Since 2.1.0)</h3> 1297 * 1298 * <p> 1299 * Mockito now preserves annotations on mocked methods and types as well as generic meta data. Previously, a mock type did not preserve 1300 * annotations on types unless they were explicitly inherited and never retained annotations on methods. As a consequence, the following 1301 * conditions now hold true: 1302 * 1303 * <pre class="code"><code class="java"> 1304 * {@literal @}{@code MyAnnotation 1305 * class Foo { 1306 * List<String> bar() { ... } 1307 * } 1308 * 1309 * Class<?> mockType = mock(Foo.class).getClass(); 1310 * assert mockType.isAnnotationPresent(MyAnnotation.class); 1311 * assert mockType.getDeclaredMethod("bar").getGenericReturnType() instanceof ParameterizedType; 1312 * }</code></pre> 1313 * 1314 * <p> 1315 * When using Java 8, Mockito now also preserves type annotations. This is default behavior and might not hold <a href="#28">if an 1316 * alternative {@link org.mockito.plugins.MockMaker} is used</a>. 1317 * 1318 * <h3 id="39">39. <a class="meaningful_link" href="#Mocking_Final" name="Mocking_Final">Mocking final types, enums and final methods</a> (Since 2.1.0)</h3> 1319 * 1320 * Mockito now offers an {@link Incubating}, optional support for mocking final classes and methods. 1321 * This is a fantastic improvement that demonstrates Mockito's everlasting quest for improving testing experience. 1322 * Our ambition is that Mockito "just works" with final classes and methods. 1323 * Previously they were considered <em>unmockable</em>, preventing the user from mocking. 1324 * We already started discussing how to make this feature enabled by default. 1325 * Currently, the feature is still optional as we wait for more feedback from the community. 1326 * 1327 * <p> 1328 * This feature is turned off by default because it is based on completely different mocking mechanism 1329 * that requires more feedback from the community. 1330 * 1331 * <p> 1332 * This alternative mock maker which uses 1333 * a combination of both Java instrumentation API and sub-classing rather than creating a new class to represent 1334 * a mock. This way, it becomes possible to mock final types and methods. 1335 * 1336 * <p> 1337 * This mock maker is <strong>turned off by default</strong> because it is based on completely different mocking mechanism 1338 * that requires more feedback from the community. It can be activated explicitly by the mockito extension mechanism, 1339 * just create in the classpath a file <code>/mockito-extensions/org.mockito.plugins.MockMaker</code> 1340 * containing the value <code>mock-maker-inline</code>. 1341 * 1342 * <p> 1343 * As a convenience, the Mockito team provides an artifact where this mock maker is preconfigured. Instead of using the 1344 * <i>mockito-core</i> artifact, include the <i>mockito-inline</i> artifact in your project. Note that this artifact is 1345 * likely to be discontinued once mocking of final classes and methods gets integrated into the default mock maker. 1346 * 1347 * <p> 1348 * Some noteworthy notes about this mock maker: 1349 * <ul> 1350 * <li>Mocking final types and enums is incompatible with mock settings like : 1351 * <ul> 1352 * <li>explicitly serialization support <code>withSettings().serializable()</code></li> 1353 * <li>extra-interfaces <code>withSettings().extraInterfaces()</code></li> 1354 * </ul> 1355 * </li> 1356 * <li>Some methods cannot be mocked 1357 * <ul> 1358 * <li>Package-visible methods of <code>java.*</code></li> 1359 * <li><code>native</code> methods</li> 1360 * </ul> 1361 * </li> 1362 * <li>This mock maker has been designed around Java Agent runtime attachment ; this require a compatible JVM, 1363 * that is part of the JDK (or Java 9 VM). When running on a non-JDK VM prior to Java 9, it is however possible to 1364 * manually add the <a href="http://bytebuddy.net">Byte Buddy Java agent jar</a> using the <code>-javaagent</code> 1365 * parameter upon starting the JVM. 1366 * </li> 1367 * </ul> 1368 * 1369 * <p> 1370 * If you are interested in more details of this feature please read the javadoc of 1371 * <code>org.mockito.internal.creation.bytebuddy.InlineByteBuddyMockMaker</code> 1372 * 1373 * <h3 id="40">40. <a class="meaningful_link" href="#strict_mockito" name="strict_mockito"> 1374 * (*new*) Improved productivity and cleaner tests with "stricter" Mockito</a> (Since 2.+)</h3> 1375 * 1376 * To quickly find out how "stricter" Mockito can make you more productive and get your tests cleaner, see: 1377 * <ul> 1378 * <li>Strict stubbing with JUnit Rules - {@link MockitoRule#strictness(Strictness)} with {@link Strictness#STRICT_STUBS}</li> 1379 * <li>Strict stubbing with JUnit Runner - {@link MockitoJUnitRunner.StrictStubs}</li> 1380 * <li>Strict stubbing if you cannot use runner/rule (like TestNG) - {@link MockitoSession}</li> 1381 * <li>Unnecessary stubbing detection with {@link MockitoJUnitRunner}</li> 1382 * <li>Stubbing argument mismatch warnings, documented in {@link MockitoHint}</li> 1383 * </ul> 1384 * 1385 * Mockito is a "loose" mocking framework by default. 1386 * Mocks can be interacted with without setting any expectations beforehand. 1387 * This is intentional and it improves the quality of tests by forcing users to be explicit about what they want to stub / verify. 1388 * It is also very intuitive, easy to use and blends nicely with "given", "when", "then" template of clean test code. 1389 * This is also different from the classic mocking frameworks of the past, they were "strict" by default. 1390 * <p> 1391 * Being "loose" by default makes Mockito tests harder to debug at times. 1392 * There are scenarios where misconfigured stubbing (like using a wrong argument) forces the user to run the test with a debugger. 1393 * Ideally, tests failures are immediately obvious and don't require debugger to identify the root cause. 1394 * Starting with version 2.1 Mockito has been getting new features that nudge the framework towards "strictness". 1395 * We want Mockito to offer fantastic debuggability while not losing its core mocking style, optimized for 1396 * intuitiveness, explicitness and clean test code. 1397 * <p> 1398 * Help Mockito! Try the new features, give us feedback, join the discussion about Mockito strictness at GitHub 1399 * <a href="https://github.com/mockito/mockito/issues/769">issue 769</a>. 1400 * 1401 * <h3 id="41">41. <a class="meaningful_link" href="#framework_integrations_api" name="framework_integrations_api"> 1402 * (**new**) Advanced public API for framework integrations (Since 2.10.+)</a></h3> 1403 * 1404 * In Summer 2017 we decided that Mockito 1405 * <a href="https://www.linkedin.com/pulse/mockito-vs-powermock-opinionated-dogmatic-static-mocking-faber"> 1406 * should offer better API 1407 * </a> 1408 * for advanced framework integrations. 1409 * The new API is not intended for users who want to write unit tests. 1410 * It is intended for other test tools and mocking frameworks that need to extend or wrap Mockito with some custom logic. 1411 * During the design and implementation process (<a href="https://github.com/mockito/mockito/issues/1110">issue 1110</a>) 1412 * we have developed and changed following public API elements: 1413 * <ul> 1414 * <li>New {@link MockitoPlugins} - 1415 * Enables framework integrators to get access to default Mockito plugins. 1416 * Useful when one needs to implement custom plugin such as {@link MockMaker} 1417 * and delegate some behavior to the default Mockito implementation. 1418 * </li> 1419 * <li>New {@link MockSettings#build(Class)} - 1420 * Creates immutable view of mock settings used later by Mockito. 1421 * Useful for creating invocations with {@link InvocationFactory} or when implementing custom {@link MockHandler}. 1422 * </li> 1423 * <li>New {@link MockingDetails#getMockHandler()} - 1424 * Other frameworks may use the mock handler to programmatically simulate invocations on mock objects. 1425 * </li> 1426 * <li>New {@link MockHandler#getMockSettings()} - 1427 * Useful to get hold of the setting the mock object was created with. 1428 * </li> 1429 * <li>New {@link InvocationFactory} - 1430 * Provides means to create instances of {@link Invocation} objects. 1431 * Useful for framework integrations that need to programmatically simulate method calls on mock objects. 1432 * </li> 1433 * <li>New {@link MockHandler#getInvocationContainer()} - 1434 * Provides access to invocation container object which has no methods (marker interface). 1435 * Container is needed to hide the internal implementation and avoid leaking it to the public API. 1436 * </li> 1437 * <li>Changed {@link Stubbing} - 1438 * it now extends {@link Answer} interface. 1439 * It is backwards compatible because Stubbing interface is not extensible (see {@link NotExtensible}). 1440 * The change should be seamless to our users. 1441 * </li> 1442 * <li>Deprecated {@link InternalMockHandler} - 1443 * In order to accommodate API changes we needed to deprecate this interface. 1444 * The interface was always documented as internal, we don't have evidence it was used by the community. 1445 * The deprecation should be completely seamless for our users. 1446 * </li> 1447 * <li>{@link NotExtensible} - 1448 * Public annotation that indicates to the user that she should not provide custom implementations of given type. 1449 * Helps framework integrators and our users understand how to use Mockito API safely. 1450 * </li> 1451 * </ul> 1452 * Do you have feedback? Please leave comment in <a href="https://github.com/mockito/mockito/issues/1110">issue 1110</a>. 1453 * 1454 * <h3 id="42">42. <a class="meaningful_link" href="#verifiation_started_listener" name="verifiation_started_listener"> 1455 * (**new**) New API for integrations: listening on verification start events (Since 2.11.+)</a></h3> 1456 * 1457 * Framework integrations such as <a href="https://projects.spring.io/spring-boot">Spring Boot</a> needs public API to tackle double-proxy use case 1458 * (<a href="https://github.com/mockito/mockito/issues/1191">issue 1191</a>). 1459 * We added: 1460 * <ul> 1461 * <li>New {@link VerificationStartedListener} and {@link VerificationStartedEvent} 1462 * enable framework integrators to replace the mock object for verification. 1463 * The main driving use case is <a href="https://projects.spring.io/spring-boot/">Spring Boot</a> integration. 1464 * For details see Javadoc for {@link VerificationStartedListener}. 1465 * </li> 1466 * <li>New public method {@link MockSettings#verificationStartedListeners(VerificationStartedListener...)} 1467 * allows to supply verification started listeners at mock creation time. 1468 * </li> 1469 * <li>New handy method {@link MockingDetails#getMock()} was added to make the {@code MockingDetails} API more complete. 1470 * We found this method useful during the implementation. 1471 * </li> 1472 * </ul> 1473 * 1474 * <h3 id="43">43. <a class="meaningful_link" href="#mockito_session_testing_frameworks" name="mockito_session_testing_frameworks"> 1475 * (**new**) New API for integrations: <code>MockitoSession</code> is usable by testing frameworks (Since 2.15.+)</a></h3> 1476 * 1477 * <p>{@link MockitoSessionBuilder} and {@link MockitoSession} were enhanced to enable reuse by testing framework 1478 * integrations (e.g. {@link MockitoRule} for JUnit):</p> 1479 * <ul> 1480 * <li>{@link MockitoSessionBuilder#initMocks(Object...)} allows to pass in multiple test class instances for 1481 * initialization of fields annotated with Mockito annotations like {@link org.mockito.Mock}. 1482 * This method is useful for advanced framework integrations (e.g. JUnit Jupiter), when a test uses multiple, 1483 * e.g. nested, test class instances. 1484 * </li> 1485 * <li>{@link MockitoSessionBuilder#name(String)} allows to pass a name from the testing framework to the 1486 * {@link MockitoSession} that will be used for printing warnings when {@link Strictness#WARN} is used. 1487 * </li> 1488 * <li>{@link MockitoSessionBuilder#logger(MockitoSessionLogger)} makes it possible to customize the logger used 1489 * for hints/warnings produced when finishing mocking (useful for testing and to connect reporting capabilities 1490 * provided by testing frameworks such as JUnit Jupiter). 1491 * </li> 1492 * <li>{@link MockitoSession#setStrictness(Strictness)} allows to change the strictness of a {@link MockitoSession} 1493 * for one-off scenarios, e.g. it enables configuring a default strictness for all tests in a class but makes it 1494 * possible to change the strictness for a single or a few tests. 1495 * </li> 1496 * <li>{@link MockitoSession#finishMocking(Throwable)} was added to avoid confusion that may arise because 1497 * there are multiple competing failures. It will disable certain checks when the supplied <em>failure</em> 1498 * is not {@code null}. 1499 * </li> 1500 * </ul> 1501 * 1502 * <h3 id="44">44. <a class="meaningful_link" href="#mockito_instantiator_provider_deprecation" name="mockito_instantiator_provider_deprecation"> 1503 * Deprecated <code>org.mockito.plugins.InstantiatorProvider</code> as it was leaking internal API. it was 1504 * replaced by <code>org.mockito.plugins.InstantiatorProvider2 (Since 2.15.4)</a></h3> 1505 * 1506 * <p>{@link org.mockito.plugins.InstantiatorProvider} returned an internal API. Hence it was deprecated and replaced 1507 * by {@link org.mockito.plugins.InstantiatorProvider2}. Old {@link org.mockito.plugins.InstantiatorProvider 1508 * instantiator providers} will continue to work, but it is recommended to switch to the new API.</p> 1509 */ 1510@SuppressWarnings("unchecked") 1511public class Mockito extends ArgumentMatchers { 1512 1513 static final MockitoCore MOCKITO_CORE = new MockitoCore(); 1514 1515 /** 1516 * The default <code>Answer</code> of every mock <b>if</b> the mock was not stubbed. 1517 * 1518 * Typically it just returns some empty value. 1519 * <p> 1520 * {@link Answer} can be used to define the return values of unstubbed invocations. 1521 * <p> 1522 * This implementation first tries the global configuration and if there is no global configuration then 1523 * it will use a default answer that returns zeros, empty collections, nulls, etc. 1524 */ 1525 public static final Answer<Object> RETURNS_DEFAULTS = Answers.RETURNS_DEFAULTS; 1526 1527 /** 1528 * Optional <code>Answer</code> to be used with {@link Mockito#mock(Class, Answer)}. 1529 * <p> 1530 * {@link Answer} can be used to define the return values of unstubbed invocations. 1531 * <p> 1532 * This implementation can be helpful when working with legacy code. 1533 * Unstubbed methods often return null. If your code uses the object returned by an unstubbed call you get a NullPointerException. 1534 * This implementation of Answer <b>returns SmartNull instead of null</b>. 1535 * <code>SmartNull</code> gives nicer exception message than NPE because it points out the line where unstubbed method was called. You just click on the stack trace. 1536 * <p> 1537 * <code>ReturnsSmartNulls</code> first tries to return ordinary values (zeros, empty collections, empty string, etc.) 1538 * then it tries to return SmartNull. If the return type is final then plain <code>null</code> is returned. 1539 * <p> 1540 * <code>ReturnsSmartNulls</code> will be probably the default return values strategy in Mockito 3.0.0 1541 * <p> 1542 * Example: 1543 * <pre class="code"><code class="java"> 1544 * Foo mock = mock(Foo.class, RETURNS_SMART_NULLS); 1545 * 1546 * //calling unstubbed method here: 1547 * Stuff stuff = mock.getStuff(); 1548 * 1549 * //using object returned by unstubbed call: 1550 * stuff.doSomething(); 1551 * 1552 * //Above doesn't yield NullPointerException this time! 1553 * //Instead, SmartNullPointerException is thrown. 1554 * //Exception's cause links to unstubbed <i>mock.getStuff()</i> - just click on the stack trace. 1555 * </code></pre> 1556 */ 1557 public static final Answer<Object> RETURNS_SMART_NULLS = Answers.RETURNS_SMART_NULLS; 1558 1559 /** 1560 * Optional <code>Answer</code> to be used with {@link Mockito#mock(Class, Answer)} 1561 * <p> 1562 * {@link Answer} can be used to define the return values of unstubbed invocations. 1563 * <p> 1564 * This implementation can be helpful when working with legacy code. 1565 * <p> 1566 * ReturnsMocks first tries to return ordinary values (zeros, empty collections, empty string, etc.) 1567 * then it tries to return mocks. If the return type cannot be mocked (e.g. is final) then plain <code>null</code> is returned. 1568 * <p> 1569 */ 1570 public static final Answer<Object> RETURNS_MOCKS = Answers.RETURNS_MOCKS; 1571 1572 /** 1573 * Optional <code>Answer</code> to be used with {@link Mockito#mock(Class, Answer)}. 1574 * <p> 1575 * Example that shows how deep stub works: 1576 * <pre class="code"><code class="java"> 1577 * Foo mock = mock(Foo.class, RETURNS_DEEP_STUBS); 1578 * 1579 * // note that we're stubbing a chain of methods here: getBar().getName() 1580 * when(mock.getBar().getName()).thenReturn("deep"); 1581 * 1582 * // note that we're chaining method calls: getBar().getName() 1583 * assertEquals("deep", mock.getBar().getName()); 1584 * </code></pre> 1585 * </p> 1586 * 1587 * <p> 1588 * <strong>WARNING: </strong> 1589 * This feature should rarely be required for regular clean code! Leave it for legacy code. 1590 * Mocking a mock to return a mock, to return a mock, (...), to return something meaningful 1591 * hints at violation of Law of Demeter or mocking a value object (a well known anti-pattern). 1592 * </p> 1593 * 1594 * <p> 1595 * Good quote I've seen one day on the web: <strong>every time a mock returns a mock a fairy dies</strong>. 1596 * </p> 1597 * 1598 * <p> 1599 * Please note that this answer will return existing mocks that matches the stub. This 1600 * behavior is ok with deep stubs and allows verification to work on the last mock of the chain. 1601 * <pre class="code"><code class="java"> 1602 * when(mock.getBar(anyString()).getThingy().getName()).thenReturn("deep"); 1603 * 1604 * mock.getBar("candy bar").getThingy().getName(); 1605 * 1606 * assertSame(mock.getBar(anyString()).getThingy().getName(), mock.getBar(anyString()).getThingy().getName()); 1607 * verify(mock.getBar("candy bar").getThingy()).getName(); 1608 * verify(mock.getBar(anyString()).getThingy()).getName(); 1609 * </code></pre> 1610 * </p> 1611 * 1612 * <p> 1613 * Verification only works with the last mock in the chain. You can use verification modes. 1614 * <pre class="code"><code class="java"> 1615 * when(person.getAddress(anyString()).getStreet().getName()).thenReturn("deep"); 1616 * when(person.getAddress(anyString()).getStreet(Locale.ITALIAN).getName()).thenReturn("deep"); 1617 * when(person.getAddress(anyString()).getStreet(Locale.CHINESE).getName()).thenReturn("deep"); 1618 * 1619 * person.getAddress("the docks").getStreet().getName(); 1620 * person.getAddress("the docks").getStreet().getLongName(); 1621 * person.getAddress("the docks").getStreet(Locale.ITALIAN).getName(); 1622 * person.getAddress("the docks").getStreet(Locale.CHINESE).getName(); 1623 * 1624 * // note that we are actually referring to the very last mock in the stubbing chain. 1625 * InOrder inOrder = inOrder( 1626 * person.getAddress("the docks").getStreet(), 1627 * person.getAddress("the docks").getStreet(Locale.CHINESE), 1628 * person.getAddress("the docks").getStreet(Locale.ITALIAN) 1629 * ); 1630 * inOrder.verify(person.getAddress("the docks").getStreet(), times(1)).getName(); 1631 * inOrder.verify(person.getAddress("the docks").getStreet()).getLongName(); 1632 * inOrder.verify(person.getAddress("the docks").getStreet(Locale.ITALIAN), atLeast(1)).getName(); 1633 * inOrder.verify(person.getAddress("the docks").getStreet(Locale.CHINESE)).getName(); 1634 * </code></pre> 1635 * </p> 1636 * 1637 * <p> 1638 * How deep stub work internally? 1639 * <pre class="code"><code class="java"> 1640 * //this: 1641 * Foo mock = mock(Foo.class, RETURNS_DEEP_STUBS); 1642 * when(mock.getBar().getName(), "deep"); 1643 * 1644 * //is equivalent of 1645 * Foo foo = mock(Foo.class); 1646 * Bar bar = mock(Bar.class); 1647 * when(foo.getBar()).thenReturn(bar); 1648 * when(bar.getName()).thenReturn("deep"); 1649 * </code></pre> 1650 * </p> 1651 * 1652 * <p> 1653 * This feature will not work when any return type of methods included in the chain cannot be mocked 1654 * (for example: is a primitive or a final class). This is because of java type system. 1655 * </p> 1656 */ 1657 public static final Answer<Object> RETURNS_DEEP_STUBS = Answers.RETURNS_DEEP_STUBS; 1658 1659 /** 1660 * Optional <code>Answer</code> to be used with {@link Mockito#mock(Class, Answer)} 1661 * <p> 1662 * {@link Answer} can be used to define the return values of unstubbed invocations. 1663 * <p> 1664 * This implementation can be helpful when working with legacy code. 1665 * When this implementation is used, unstubbed methods will delegate to the real implementation. 1666 * This is a way to create a partial mock object that calls real methods by default. 1667 * <p> 1668 * As usual you are going to read <b>the partial mock warning</b>: 1669 * Object oriented programming is more less tackling complexity by dividing the complexity into separate, specific, SRPy objects. 1670 * How does partial mock fit into this paradigm? Well, it just doesn't... 1671 * Partial mock usually means that the complexity has been moved to a different method on the same object. 1672 * In most cases, this is not the way you want to design your application. 1673 * <p> 1674 * However, there are rare cases when partial mocks come handy: 1675 * dealing with code you cannot change easily (3rd party interfaces, interim refactoring of legacy code etc.) 1676 * However, I wouldn't use partial mocks for new, test-driven & well-designed code. 1677 * <p> 1678 * Example: 1679 * <pre class="code"><code class="java"> 1680 * Foo mock = mock(Foo.class, CALLS_REAL_METHODS); 1681 * 1682 * // this calls the real implementation of Foo.getSomething() 1683 * value = mock.getSomething(); 1684 * 1685 * doReturn(fakeValue).when(mock).getSomething(); 1686 * 1687 * // now fakeValue is returned 1688 * value = mock.getSomething(); 1689 * </code></pre> 1690 * 1691 * <p> 1692 * <u>Note:</u> Stubbing partial mocks using <code>when(mock.getSomething()).thenReturn(fakeValue)</code> 1693 * syntax will call the real method. For partial mock it's recommended to use <code>doReturn</code> syntax. 1694 */ 1695 public static final Answer<Object> CALLS_REAL_METHODS = Answers.CALLS_REAL_METHODS; 1696 1697 /** 1698 * Optional <code>Answer</code> to be used with {@link Mockito#mock(Class, Answer)}. 1699 * 1700 * Allows Builder mocks to return itself whenever a method is invoked that returns a Type equal 1701 * to the class or a superclass. 1702 * 1703 * <p><b>Keep in mind this answer uses the return type of a method. 1704 * If this type is assignable to the class of the mock, it will return the mock. 1705 * Therefore if you have a method returning a superclass (for example {@code Object}) it will match and return the mock.</b></p> 1706 * 1707 * Consider a HttpBuilder used in a HttpRequesterWithHeaders. 1708 * 1709 * <pre class="code"><code class="java"> 1710 * public class HttpRequesterWithHeaders { 1711 * 1712 * private HttpBuilder builder; 1713 * 1714 * public HttpRequesterWithHeaders(HttpBuilder builder) { 1715 * this.builder = builder; 1716 * } 1717 * 1718 * public String request(String uri) { 1719 * return builder.withUrl(uri) 1720 * .withHeader("Content-type: application/json") 1721 * .withHeader("Authorization: Bearer") 1722 * .request(); 1723 * } 1724 * } 1725 * 1726 * private static class HttpBuilder { 1727 * 1728 * private String uri; 1729 * private List<String> headers; 1730 * 1731 * public HttpBuilder() { 1732 * this.headers = new ArrayList<String>(); 1733 * } 1734 * 1735 * public HttpBuilder withUrl(String uri) { 1736 * this.uri = uri; 1737 * return this; 1738 * } 1739 * 1740 * public HttpBuilder withHeader(String header) { 1741 * this.headers.add(header); 1742 * return this; 1743 * } 1744 * 1745 * public String request() { 1746 * return uri + headers.toString(); 1747 * } 1748 * } 1749 * </code></pre> 1750 * 1751 * The following test will succeed 1752 * 1753 * <pre><code> 1754 * @Test 1755 * public void use_full_builder_with_terminating_method() { 1756 * HttpBuilder builder = mock(HttpBuilder.class, RETURNS_SELF); 1757 * HttpRequesterWithHeaders requester = new HttpRequesterWithHeaders(builder); 1758 * String response = "StatusCode: 200"; 1759 * 1760 * when(builder.request()).thenReturn(response); 1761 * 1762 * assertThat(requester.request("URI")).isEqualTo(response); 1763 * } 1764 * </code></pre> 1765 */ 1766 public static final Answer<Object> RETURNS_SELF = Answers.RETURNS_SELF; 1767 1768 /** 1769 * Creates mock object of given class or interface. 1770 * <p> 1771 * See examples in javadoc for {@link Mockito} class 1772 * 1773 * @param classToMock class or interface to mock 1774 * @return mock object 1775 */ 1776 public static <T> T mock(Class<T> classToMock) { 1777 return mock(classToMock, withSettings()); 1778 } 1779 1780 /** 1781 * Specifies mock name. Naming mocks can be helpful for debugging - the name is used in all verification errors. 1782 * <p> 1783 * Beware that naming mocks is not a solution for complex code which uses too many mocks or collaborators. 1784 * <b>If you have too many mocks then refactor the code</b> so that it's easy to test/debug without necessity of naming mocks. 1785 * <p> 1786 * <b>If you use <code>@Mock</code> annotation then you've got naming mocks for free!</b> <code>@Mock</code> uses field name as mock name. {@link Mock Read more.} 1787 * <p> 1788 * 1789 * See examples in javadoc for {@link Mockito} class 1790 * 1791 * @param classToMock class or interface to mock 1792 * @param name of the mock 1793 * @return mock object 1794 */ 1795 public static <T> T mock(Class<T> classToMock, String name) { 1796 return mock(classToMock, withSettings() 1797 .name(name) 1798 .defaultAnswer(RETURNS_DEFAULTS)); 1799 } 1800 1801 /** 1802 * Returns a MockingDetails instance that enables inspecting a particular object for Mockito related information. 1803 * Can be used to find out if given object is a Mockito mock 1804 * or to find out if a given mock is a spy or mock. 1805 * <p> 1806 * In future Mockito versions MockingDetails may grow and provide other useful information about the mock, 1807 * e.g. invocations, stubbing info, etc. 1808 * 1809 * @param toInspect - object to inspect. null input is allowed. 1810 * @return A {@link org.mockito.MockingDetails} instance. 1811 * @since 1.9.5 1812 */ 1813 public static MockingDetails mockingDetails(Object toInspect) { 1814 return MOCKITO_CORE.mockingDetails(toInspect); 1815 } 1816 1817 /** 1818 * Creates mock with a specified strategy for its answers to interactions. 1819 * It's quite an advanced feature and typically you don't need it to write decent tests. 1820 * However it can be helpful when working with legacy systems. 1821 * <p> 1822 * It is the default answer so it will be used <b>only when you don't</b> stub the method call. 1823 * 1824 * <pre class="code"><code class="java"> 1825 * Foo mock = mock(Foo.class, RETURNS_SMART_NULLS); 1826 * Foo mockTwo = mock(Foo.class, new YourOwnAnswer()); 1827 * </code></pre> 1828 * 1829 * <p>See examples in javadoc for {@link Mockito} class</p> 1830 * 1831 * @param classToMock class or interface to mock 1832 * @param defaultAnswer default answer for unstubbed methods 1833 * 1834 * @return mock object 1835 */ 1836 public static <T> T mock(Class<T> classToMock, Answer defaultAnswer) { 1837 return mock(classToMock, withSettings().defaultAnswer(defaultAnswer)); 1838 } 1839 1840 /** 1841 * Creates a mock with some non-standard settings. 1842 * <p> 1843 * The number of configuration points for a mock grows 1844 * so we need a fluent way to introduce new configuration without adding more and more overloaded Mockito.mock() methods. 1845 * Hence {@link MockSettings}. 1846 * <pre class="code"><code class="java"> 1847 * Listener mock = mock(Listener.class, withSettings() 1848 * .name("firstListner").defaultBehavior(RETURNS_SMART_NULLS)); 1849 * ); 1850 * </code></pre> 1851 * <b>Use it carefully and occasionally</b>. What might be reason your test needs non-standard mocks? 1852 * Is the code under test so complicated that it requires non-standard mocks? 1853 * Wouldn't you prefer to refactor the code under test so it is testable in a simple way? 1854 * <p> 1855 * See also {@link Mockito#withSettings()} 1856 * <p> 1857 * See examples in javadoc for {@link Mockito} class 1858 * 1859 * @param classToMock class or interface to mock 1860 * @param mockSettings additional mock settings 1861 * @return mock object 1862 */ 1863 public static <T> T mock(Class<T> classToMock, MockSettings mockSettings) { 1864 return MOCKITO_CORE.mock(classToMock, mockSettings); 1865 } 1866 1867 /** 1868 * Creates a spy of the real object. The spy calls <b>real</b> methods unless they are stubbed. 1869 * <p> 1870 * Real spies should be used <b>carefully and occasionally</b>, for example when dealing with legacy code. 1871 * <p> 1872 * As usual you are going to read <b>the partial mock warning</b>: 1873 * Object oriented programming tackles complexity by dividing the complexity into separate, specific, SRPy objects. 1874 * How does partial mock fit into this paradigm? Well, it just doesn't... 1875 * Partial mock usually means that the complexity has been moved to a different method on the same object. 1876 * In most cases, this is not the way you want to design your application. 1877 * <p> 1878 * However, there are rare cases when partial mocks come handy: 1879 * dealing with code you cannot change easily (3rd party interfaces, interim refactoring of legacy code etc.) 1880 * However, I wouldn't use partial mocks for new, test-driven & well-designed code. 1881 * <p> 1882 * Example: 1883 * 1884 * <pre class="code"><code class="java"> 1885 * List list = new LinkedList(); 1886 * List spy = spy(list); 1887 * 1888 * //optionally, you can stub out some methods: 1889 * when(spy.size()).thenReturn(100); 1890 * 1891 * //using the spy calls <b>real</b> methods 1892 * spy.add("one"); 1893 * spy.add("two"); 1894 * 1895 * //prints "one" - the first element of a list 1896 * System.out.println(spy.get(0)); 1897 * 1898 * //size() method was stubbed - 100 is printed 1899 * System.out.println(spy.size()); 1900 * 1901 * //optionally, you can verify 1902 * verify(spy).add("one"); 1903 * verify(spy).add("two"); 1904 * </code></pre> 1905 * 1906 * <h4>Important gotcha on spying real objects!</h4> 1907 * <ol> 1908 * <li>Sometimes it's impossible or impractical to use {@link Mockito#when(Object)} for stubbing spies. 1909 * Therefore for spies it is recommended to always use <code>doReturn</code>|<code>Answer</code>|<code>Throw()</code>|<code>CallRealMethod</code> 1910 * family of methods for stubbing. Example: 1911 * 1912 * <pre class="code"><code class="java"> 1913 * List list = new LinkedList(); 1914 * List spy = spy(list); 1915 * 1916 * //Impossible: real method is called so spy.get(0) throws IndexOutOfBoundsException (the list is yet empty) 1917 * when(spy.get(0)).thenReturn("foo"); 1918 * 1919 * //You have to use doReturn() for stubbing 1920 * doReturn("foo").when(spy).get(0); 1921 * </code></pre> 1922 * </li> 1923 * 1924 * <li>Mockito <b>*does not*</b> delegate calls to the passed real instance, instead it actually creates a copy of it. 1925 * So if you keep the real instance and interact with it, don't expect the spied to be aware of those interaction 1926 * and their effect on real instance state. 1927 * The corollary is that when an <b>*unstubbed*</b> method is called <b>*on the spy*</b> but <b>*not on the real instance*</b>, 1928 * you won't see any effects on the real instance.</li> 1929 * 1930 * <li>Watch out for final methods. 1931 * Mockito doesn't mock final methods so the bottom line is: when you spy on real objects + you try to stub a final method = trouble. 1932 * Also you won't be able to verify those method as well. 1933 * </li> 1934 * </ol> 1935 * <p> 1936 * See examples in javadoc for {@link Mockito} class 1937 * 1938 * <p>Note that the spy won't have any annotations of the spied type, because CGLIB won't rewrite them. 1939 * It may troublesome for code that rely on the spy to have these annotations.</p> 1940 * 1941 * 1942 * @param object 1943 * to spy on 1944 * @return a spy of the real object 1945 */ 1946 public static <T> T spy(T object) { 1947 return MOCKITO_CORE.mock((Class<T>) object.getClass(), withSettings() 1948 .spiedInstance(object) 1949 .defaultAnswer(CALLS_REAL_METHODS)); 1950 } 1951 1952 /** 1953 * Please refer to the documentation of {@link #spy(Object)}. 1954 * Overusing spies hints at code design smells. 1955 * <p> 1956 * This method, in contrast to the original {@link #spy(Object)}, creates a spy based on class instead of an object. 1957 * Sometimes it is more convenient to create spy based on the class and avoid providing an instance of a spied object. 1958 * This is particularly useful for spying on abstract classes because they cannot be instantiated. 1959 * See also {@link MockSettings#useConstructor(Object...)}. 1960 * <p> 1961 * Examples: 1962 * <pre class="code"><code class="java"> 1963 * SomeAbstract spy = spy(SomeAbstract.class); 1964 * 1965 * //Robust API, via settings builder: 1966 * OtherAbstract spy = mock(OtherAbstract.class, withSettings() 1967 * .useConstructor().defaultAnswer(CALLS_REAL_METHODS)); 1968 * 1969 * //Mocking a non-static inner abstract class: 1970 * InnerAbstract spy = mock(InnerAbstract.class, withSettings() 1971 * .useConstructor().outerInstance(outerInstance).defaultAnswer(CALLS_REAL_METHODS)); 1972 * </code></pre> 1973 * 1974 * @param classToSpy the class to spy 1975 * @param <T> type of the spy 1976 * @return a spy of the provided class 1977 * @since 1.10.12 1978 */ 1979 @Incubating 1980 public static <T> T spy(Class<T> classToSpy) { 1981 return MOCKITO_CORE.mock(classToSpy, withSettings() 1982 .useConstructor() 1983 .defaultAnswer(CALLS_REAL_METHODS)); 1984 } 1985 1986 /** 1987 * Enables stubbing methods. Use it when you want the mock to return particular value when particular method is called. 1988 * <p> 1989 * Simply put: "<b>When</b> the x method is called <b>then</b> return y". 1990 * 1991 * <p> 1992 * Examples: 1993 * 1994 * <pre class="code"><code class="java"> 1995 * <b>when</b>(mock.someMethod()).<b>thenReturn</b>(10); 1996 * 1997 * //you can use flexible argument matchers, e.g: 1998 * when(mock.someMethod(<b>anyString()</b>)).thenReturn(10); 1999 * 2000 * //setting exception to be thrown: 2001 * when(mock.someMethod("some arg")).thenThrow(new RuntimeException()); 2002 * 2003 * //you can set different behavior for consecutive method calls. 2004 * //Last stubbing (e.g: thenReturn("foo")) determines the behavior of further consecutive calls. 2005 * when(mock.someMethod("some arg")) 2006 * .thenThrow(new RuntimeException()) 2007 * .thenReturn("foo"); 2008 * 2009 * //Alternative, shorter version for consecutive stubbing: 2010 * when(mock.someMethod("some arg")) 2011 * .thenReturn("one", "two"); 2012 * //is the same as: 2013 * when(mock.someMethod("some arg")) 2014 * .thenReturn("one") 2015 * .thenReturn("two"); 2016 * 2017 * //shorter version for consecutive method calls throwing exceptions: 2018 * when(mock.someMethod("some arg")) 2019 * .thenThrow(new RuntimeException(), new NullPointerException(); 2020 * 2021 * </code></pre> 2022 * 2023 * For stubbing void methods with throwables see: {@link Mockito#doThrow(Throwable...)} 2024 * <p> 2025 * Stubbing can be overridden: for example common stubbing can go to fixture 2026 * setup but the test methods can override it. 2027 * Please note that overridding stubbing is a potential code smell that points out too much stubbing. 2028 * <p> 2029 * Once stubbed, the method will always return stubbed value regardless 2030 * of how many times it is called. 2031 * <p> 2032 * Last stubbing is more important - when you stubbed the same method with 2033 * the same arguments many times. 2034 * <p> 2035 * Although it is possible to verify a stubbed invocation, usually <b>it's just redundant</b>. 2036 * Let's say you've stubbed <code>foo.bar()</code>. 2037 * If your code cares what <code>foo.bar()</code> returns then something else breaks(often before even <code>verify()</code> gets executed). 2038 * If your code doesn't care what <code>get(0)</code> returns then it should not be stubbed. 2039 * Not convinced? See <a href="http://monkeyisland.pl/2008/04/26/asking-and-telling">here</a>. 2040 * 2041 * <p> 2042 * See examples in javadoc for {@link Mockito} class 2043 * @param methodCall method to be stubbed 2044 * @return OngoingStubbing object used to stub fluently. 2045 * <strong>Do not</strong> create a reference to this returned object. 2046 */ 2047 @CheckReturnValue 2048 public static <T> OngoingStubbing<T> when(T methodCall) { 2049 return MOCKITO_CORE.when(methodCall); 2050 } 2051 2052 /** 2053 * Verifies certain behavior <b>happened once</b>. 2054 * <p> 2055 * Alias to <code>verify(mock, times(1))</code> E.g: 2056 * <pre class="code"><code class="java"> 2057 * verify(mock).someMethod("some arg"); 2058 * </code></pre> 2059 * Above is equivalent to: 2060 * <pre class="code"><code class="java"> 2061 * verify(mock, times(1)).someMethod("some arg"); 2062 * </code></pre> 2063 * <p> 2064 * Arguments passed are compared using <code>equals()</code> method. 2065 * Read about {@link ArgumentCaptor} or {@link ArgumentMatcher} to find out other ways of matching / asserting arguments passed. 2066 * <p> 2067 * Although it is possible to verify a stubbed invocation, usually <b>it's just redundant</b>. 2068 * Let's say you've stubbed <code>foo.bar()</code>. 2069 * If your code cares what <code>foo.bar()</code> returns then something else breaks(often before even <code>verify()</code> gets executed). 2070 * If your code doesn't care what <code>get(0)</code> returns then it should not be stubbed. 2071 * Not convinced? See <a href="http://monkeyisland.pl/2008/04/26/asking-and-telling">here</a>. 2072 * 2073 * <p> 2074 * See examples in javadoc for {@link Mockito} class 2075 * 2076 * @param mock to be verified 2077 * @return mock object itself 2078 */ 2079 @CheckReturnValue 2080 public static <T> T verify(T mock) { 2081 return MOCKITO_CORE.verify(mock, times(1)); 2082 } 2083 2084 /** 2085 * Verifies certain behavior happened at least once / exact number of times / never. E.g: 2086 * <pre class="code"><code class="java"> 2087 * verify(mock, times(5)).someMethod("was called five times"); 2088 * 2089 * verify(mock, atLeast(2)).someMethod("was called at least two times"); 2090 * 2091 * //you can use flexible argument matchers, e.g: 2092 * verify(mock, atLeastOnce()).someMethod(<b>anyString()</b>); 2093 * </code></pre> 2094 * 2095 * <b>times(1) is the default</b> and can be omitted 2096 * <p> 2097 * Arguments passed are compared using <code>equals()</code> method. 2098 * Read about {@link ArgumentCaptor} or {@link ArgumentMatcher} to find out other ways of matching / asserting arguments passed. 2099 * <p> 2100 * 2101 * @param mock to be verified 2102 * @param mode times(x), atLeastOnce() or never() 2103 * 2104 * @return mock object itself 2105 */ 2106 @CheckReturnValue 2107 public static <T> T verify(T mock, VerificationMode mode) { 2108 return MOCKITO_CORE.verify(mock, mode); 2109 } 2110 2111 /** 2112 * Smart Mockito users hardly use this feature because they know it could be a sign of poor tests. 2113 * Normally, you don't need to reset your mocks, just create new mocks for each test method. 2114 * <p> 2115 * Instead of <code>#reset()</code> please consider writing simple, small and focused test methods over lengthy, over-specified tests. 2116 * <b>First potential code smell is <code>reset()</code> in the middle of the test method.</b> This probably means you're testing too much. 2117 * Follow the whisper of your test methods: "Please keep us small & focused on single behavior". 2118 * There are several threads about it on mockito mailing list. 2119 * <p> 2120 * The only reason we added <code>reset()</code> method is to 2121 * make it possible to work with container-injected mocks. 2122 * For more information see the FAQ (<a href="https://github.com/mockito/mockito/wiki/FAQ">here</a>). 2123 * <p> 2124 * <b>Don't harm yourself.</b> <code>reset()</code> in the middle of the test method is a code smell (you're probably testing too much). 2125 * <pre class="code"><code class="java"> 2126 * List mock = mock(List.class); 2127 * when(mock.size()).thenReturn(10); 2128 * mock.add(1); 2129 * 2130 * reset(mock); 2131 * //at this point the mock forgot any interactions & stubbing 2132 * </code></pre> 2133 * 2134 * @param <T> The Type of the mocks 2135 * @param mocks to be reset 2136 */ 2137 public static <T> void reset(T ... mocks) { 2138 MOCKITO_CORE.reset(mocks); 2139 } 2140 2141 /** 2142 * Use this method in order to only clear invocations, when stubbing is non-trivial. Use-cases can be: 2143 * <ul> 2144 * <li>You are using a dependency injection framework to inject your mocks.</li> 2145 * <li>The mock is used in a stateful scenario. For example a class is Singleton which depends on your mock.</li> 2146 * </ul> 2147 * 2148 * <b>Try to avoid this method at all costs. Only clear invocations if you are unable to efficiently test your program.</b> 2149 * @param <T> The type of the mocks 2150 * @param mocks The mocks to clear the invocations for 2151 */ 2152 public static <T> void clearInvocations(T ... mocks) { 2153 MOCKITO_CORE.clearInvocations(mocks); 2154 } 2155 2156 /** 2157 * Checks if any of given mocks has any unverified interaction. 2158 * <p> 2159 * You can use this method after you verified your mocks - to make sure that nothing 2160 * else was invoked on your mocks. 2161 * <p> 2162 * See also {@link Mockito#never()} - it is more explicit and communicates the intent well. 2163 * <p> 2164 * Stubbed invocations (if called) are also treated as interactions. 2165 * If you want stubbed invocations automatically verified, check out {@link Strictness#STRICT_STUBS} feature 2166 * introduced in Mockito 2.3.0. 2167 * If you want to ignore stubs for verification, see {@link #ignoreStubs(Object...)}. 2168 * <p> 2169 * A word of <b>warning</b>: 2170 * Some users who did a lot of classic, expect-run-verify mocking tend to use <code>verifyNoMoreInteractions()</code> very often, even in every test method. 2171 * <code>verifyNoMoreInteractions()</code> is not recommended to use in every test method. 2172 * <code>verifyNoMoreInteractions()</code> is a handy assertion from the interaction testing toolkit. Use it only when it's relevant. 2173 * Abusing it leads to overspecified, less maintainable tests. You can find further reading 2174 * <a href="http://monkeyisland.pl/2008/07/12/should-i-worry-about-the-unexpected/">here</a>. 2175 * <p> 2176 * This method will also detect unverified invocations that occurred before the test method, 2177 * for example: in <code>setUp()</code>, <code>@Before</code> method or in constructor. 2178 * Consider writing nice code that makes interactions only in test methods. 2179 * 2180 * <p> 2181 * Example: 2182 * 2183 * <pre class="code"><code class="java"> 2184 * //interactions 2185 * mock.doSomething(); 2186 * mock.doSomethingUnexpected(); 2187 * 2188 * //verification 2189 * verify(mock).doSomething(); 2190 * 2191 * //following will fail because 'doSomethingUnexpected()' is unexpected 2192 * verifyNoMoreInteractions(mock); 2193 * 2194 * </code></pre> 2195 * 2196 * See examples in javadoc for {@link Mockito} class 2197 * 2198 * @param mocks to be verified 2199 */ 2200 public static void verifyNoMoreInteractions(Object... mocks) { 2201 MOCKITO_CORE.verifyNoMoreInteractions(mocks); 2202 } 2203 2204 /** 2205 * Verifies that no interactions happened on given mocks beyond the previously verified interactions.<br/> 2206 * This method has the same behavior as {@link #verifyNoMoreInteractions(Object...)}. 2207 * 2208 * @param mocks to be verified 2209 */ 2210 public static void verifyZeroInteractions(Object... mocks) { 2211 MOCKITO_CORE.verifyNoMoreInteractions(mocks); 2212 } 2213 2214 /** 2215 * Use <code>doThrow()</code> when you want to stub the void method with an exception. 2216 * <p> 2217 * Stubbing voids requires different approach from {@link Mockito#when(Object)} because the compiler 2218 * does not like void methods inside brackets... 2219 * <p> 2220 * Example: 2221 * 2222 * <pre class="code"><code class="java"> 2223 * doThrow(new RuntimeException()).when(mock).someVoidMethod(); 2224 * </code></pre> 2225 * 2226 * @param toBeThrown to be thrown when the stubbed method is called 2227 * @return stubber - to select a method for stubbing 2228 */ 2229 @CheckReturnValue 2230 public static Stubber doThrow(Throwable... toBeThrown) { 2231 return MOCKITO_CORE.stubber().doThrow(toBeThrown); 2232 } 2233 2234 /** 2235 * Use <code>doThrow()</code> when you want to stub the void method with an exception. 2236 * <p> 2237 * A new exception instance will be created for each method invocation. 2238 * <p> 2239 * Stubbing voids requires different approach from {@link Mockito#when(Object)} because the compiler 2240 * does not like void methods inside brackets... 2241 * <p> 2242 * Example: 2243 * 2244 * <pre class="code"><code class="java"> 2245 * doThrow(RuntimeException.class).when(mock).someVoidMethod(); 2246 * </code></pre> 2247 * 2248 * @param toBeThrown to be thrown when the stubbed method is called 2249 * @return stubber - to select a method for stubbing 2250 * @since 2.1.0 2251 */ 2252 @CheckReturnValue 2253 public static Stubber doThrow(Class<? extends Throwable> toBeThrown) { 2254 return MOCKITO_CORE.stubber().doThrow(toBeThrown); 2255 } 2256 2257 /** 2258 * Same as {@link #doThrow(Class)} but sets consecutive exception classes to be thrown. Remember to use 2259 * <code>doThrow()</code> when you want to stub the void method to throw several exception of specified class. 2260 * <p> 2261 * A new exception instance will be created for each method invocation. 2262 * <p> 2263 * Stubbing voids requires different approach from {@link Mockito#when(Object)} because the compiler 2264 * does not like void methods inside brackets... 2265 * <p> 2266 * Example: 2267 * 2268 * <pre class="code"><code class="java"> 2269 * doThrow(RuntimeException.class, BigFailure.class).when(mock).someVoidMethod(); 2270 * </code></pre> 2271 * 2272 * @param toBeThrown to be thrown when the stubbed method is called 2273 * @param toBeThrownNext next to be thrown when the stubbed method is called 2274 * @return stubber - to select a method for stubbing 2275 * @since 2.1.0 2276 */ 2277 // Additional method helps users of JDK7+ to hide heap pollution / unchecked generics array creation 2278 @SuppressWarnings ({"unchecked", "varargs"}) 2279 @CheckReturnValue 2280 public static Stubber doThrow(Class<? extends Throwable> toBeThrown, Class<? extends Throwable>... toBeThrownNext) { 2281 return MOCKITO_CORE.stubber().doThrow(toBeThrown, toBeThrownNext); 2282 } 2283 2284 2285 /** 2286 * Use <code>doCallRealMethod()</code> when you want to call the real implementation of a method. 2287 * <p> 2288 * As usual you are going to read <b>the partial mock warning</b>: 2289 * Object oriented programming is more less tackling complexity by dividing the complexity into separate, specific, SRPy objects. 2290 * How does partial mock fit into this paradigm? Well, it just doesn't... 2291 * Partial mock usually means that the complexity has been moved to a different method on the same object. 2292 * In most cases, this is not the way you want to design your application. 2293 * <p> 2294 * However, there are rare cases when partial mocks come handy: 2295 * dealing with code you cannot change easily (3rd party interfaces, interim refactoring of legacy code etc.) 2296 * However, I wouldn't use partial mocks for new, test-driven & well-designed code. 2297 * <p> 2298 * See also javadoc {@link Mockito#spy(Object)} to find out more about partial mocks. 2299 * <b>Mockito.spy() is a recommended way of creating partial mocks.</b> 2300 * The reason is it guarantees real methods are called against correctly constructed object because you're responsible for constructing the object passed to spy() method. 2301 * <p> 2302 * Example: 2303 * <pre class="code"><code class="java"> 2304 * Foo mock = mock(Foo.class); 2305 * doCallRealMethod().when(mock).someVoidMethod(); 2306 * 2307 * // this will call the real implementation of Foo.someVoidMethod() 2308 * mock.someVoidMethod(); 2309 * </code></pre> 2310 * <p> 2311 * See examples in javadoc for {@link Mockito} class 2312 * 2313 * @return stubber - to select a method for stubbing 2314 * @since 1.9.5 2315 */ 2316 @CheckReturnValue 2317 public static Stubber doCallRealMethod() { 2318 return MOCKITO_CORE.stubber().doCallRealMethod(); 2319 } 2320 2321 /** 2322 * Use <code>doAnswer()</code> when you want to stub a void method with generic {@link Answer}. 2323 * <p> 2324 * Stubbing voids requires different approach from {@link Mockito#when(Object)} because the compiler does not like void methods inside brackets... 2325 * <p> 2326 * Example: 2327 * 2328 * <pre class="code"><code class="java"> 2329 * doAnswer(new Answer() { 2330 * public Object answer(InvocationOnMock invocation) { 2331 * Object[] args = invocation.getArguments(); 2332 * Mock mock = invocation.getMock(); 2333 * return null; 2334 * }}) 2335 * .when(mock).someMethod(); 2336 * </code></pre> 2337 * <p> 2338 * See examples in javadoc for {@link Mockito} class 2339 * 2340 * @param answer to answer when the stubbed method is called 2341 * @return stubber - to select a method for stubbing 2342 */ 2343 @CheckReturnValue 2344 public static Stubber doAnswer(Answer answer) { 2345 return MOCKITO_CORE.stubber().doAnswer(answer); 2346 } 2347 2348 /** 2349 * Use <code>doNothing()</code> for setting void methods to do nothing. <b>Beware that void methods on mocks do nothing by default!</b> 2350 * However, there are rare situations when doNothing() comes handy: 2351 * <p> 2352 * <ol> 2353 * <li>Stubbing consecutive calls on a void method: 2354 * <pre class="code"><code class="java"> 2355 * doNothing(). 2356 * doThrow(new RuntimeException()) 2357 * .when(mock).someVoidMethod(); 2358 * 2359 * //does nothing the first time: 2360 * mock.someVoidMethod(); 2361 * 2362 * //throws RuntimeException the next time: 2363 * mock.someVoidMethod(); 2364 * </code></pre> 2365 * </li> 2366 * <li>When you spy real objects and you want the void method to do nothing: 2367 * <pre class="code"><code class="java"> 2368 * List list = new LinkedList(); 2369 * List spy = spy(list); 2370 * 2371 * //let's make clear() do nothing 2372 * doNothing().when(spy).clear(); 2373 * 2374 * spy.add("one"); 2375 * 2376 * //clear() does nothing, so the list still contains "one" 2377 * spy.clear(); 2378 * </code></pre> 2379 * </li> 2380 * </ol> 2381 * <p> 2382 * See examples in javadoc for {@link Mockito} class 2383 * 2384 * @return stubber - to select a method for stubbing 2385 */ 2386 @CheckReturnValue 2387 public static Stubber doNothing() { 2388 return MOCKITO_CORE.stubber().doNothing(); 2389 } 2390 2391 /** 2392 * Use <code>doReturn()</code> in those rare occasions when you cannot use {@link Mockito#when(Object)}. 2393 * <p> 2394 * <b>Beware that {@link Mockito#when(Object)} is always recommended for stubbing because it is argument type-safe 2395 * and more readable</b> (especially when stubbing consecutive calls). 2396 * <p> 2397 * Here are those rare occasions when doReturn() comes handy: 2398 * <p> 2399 * 2400 * <ol> 2401 * <li>When spying real objects and calling real methods on a spy brings side effects 2402 * 2403 * <pre class="code"><code class="java"> 2404 * List list = new LinkedList(); 2405 * List spy = spy(list); 2406 * 2407 * //Impossible: real method is called so spy.get(0) throws IndexOutOfBoundsException (the list is yet empty) 2408 * when(spy.get(0)).thenReturn("foo"); 2409 * 2410 * //You have to use doReturn() for stubbing: 2411 * doReturn("foo").when(spy).get(0); 2412 * </code></pre> 2413 * </li> 2414 * 2415 * <li>Overriding a previous exception-stubbing: 2416 * <pre class="code"><code class="java"> 2417 * when(mock.foo()).thenThrow(new RuntimeException()); 2418 * 2419 * //Impossible: the exception-stubbed foo() method is called so RuntimeException is thrown. 2420 * when(mock.foo()).thenReturn("bar"); 2421 * 2422 * //You have to use doReturn() for stubbing: 2423 * doReturn("bar").when(mock).foo(); 2424 * </code></pre> 2425 * </li> 2426 * </ol> 2427 * 2428 * Above scenarios shows a tradeoff of Mockito's elegant syntax. Note that the scenarios are very rare, though. 2429 * Spying should be sporadic and overriding exception-stubbing is very rare. Not to mention that in general 2430 * overridding stubbing is a potential code smell that points out too much stubbing. 2431 * <p> 2432 * See examples in javadoc for {@link Mockito} class 2433 * 2434 * @param toBeReturned to be returned when the stubbed method is called 2435 * @return stubber - to select a method for stubbing 2436 */ 2437 @CheckReturnValue 2438 public static Stubber doReturn(Object toBeReturned) { 2439 return MOCKITO_CORE.stubber().doReturn(toBeReturned); 2440 } 2441 2442 /** 2443 * Same as {@link #doReturn(Object)} but sets consecutive values to be returned. Remember to use 2444 * <code>doReturn()</code> in those rare occasions when you cannot use {@link Mockito#when(Object)}. 2445 * <p> 2446 * <b>Beware that {@link Mockito#when(Object)} is always recommended for stubbing because it is argument type-safe 2447 * and more readable</b> (especially when stubbing consecutive calls). 2448 * <p> 2449 * Here are those rare occasions when doReturn() comes handy: 2450 * <p> 2451 * 2452 * <ol> 2453 * <li>When spying real objects and calling real methods on a spy brings side effects 2454 * 2455 * <pre class="code"><code class="java"> 2456 * List list = new LinkedList(); 2457 * List spy = spy(list); 2458 * 2459 * //Impossible: real method is called so spy.get(0) throws IndexOutOfBoundsException (the list is yet empty) 2460 * when(spy.get(0)).thenReturn("foo", "bar", "qix"); 2461 * 2462 * //You have to use doReturn() for stubbing: 2463 * doReturn("foo", "bar", "qix").when(spy).get(0); 2464 * </code></pre> 2465 * </li> 2466 * 2467 * <li>Overriding a previous exception-stubbing: 2468 * <pre class="code"><code class="java"> 2469 * when(mock.foo()).thenThrow(new RuntimeException()); 2470 * 2471 * //Impossible: the exception-stubbed foo() method is called so RuntimeException is thrown. 2472 * when(mock.foo()).thenReturn("bar", "foo", "qix"); 2473 * 2474 * //You have to use doReturn() for stubbing: 2475 * doReturn("bar", "foo", "qix").when(mock).foo(); 2476 * </code></pre> 2477 * </li> 2478 * </ol> 2479 * 2480 * Above scenarios shows a trade-off of Mockito's elegant syntax. Note that the scenarios are very rare, though. 2481 * Spying should be sporadic and overriding exception-stubbing is very rare. Not to mention that in general 2482 * overridding stubbing is a potential code smell that points out too much stubbing. 2483 * <p> 2484 * See examples in javadoc for {@link Mockito} class 2485 * 2486 * @param toBeReturned to be returned when the stubbed method is called 2487 * @param toBeReturnedNext to be returned in consecutive calls when the stubbed method is called 2488 * @return stubber - to select a method for stubbing 2489 * @since 2.1.0 2490 */ 2491 @SuppressWarnings({"unchecked", "varargs"}) 2492 @CheckReturnValue 2493 public static Stubber doReturn(Object toBeReturned, Object... toBeReturnedNext) { 2494 return MOCKITO_CORE.stubber().doReturn(toBeReturned, toBeReturnedNext); 2495 } 2496 2497 /** 2498 * Creates {@link org.mockito.InOrder} object that allows verifying mocks in order. 2499 * 2500 * <pre class="code"><code class="java"> 2501 * InOrder inOrder = inOrder(firstMock, secondMock); 2502 * 2503 * inOrder.verify(firstMock).add("was called first"); 2504 * inOrder.verify(secondMock).add("was called second"); 2505 * </code></pre> 2506 * 2507 * Verification in order is flexible - <b>you don't have to verify all interactions</b> one-by-one 2508 * but only those that you are interested in testing in order. 2509 * <p> 2510 * Also, you can create InOrder object passing only mocks that are relevant for in-order verification. 2511 * <p> 2512 * <code>InOrder</code> verification is 'greedy', but you will hardly ever notice it. 2513 * If you want to find out more, read 2514 * <a href="https://github.com/mockito/mockito/wiki/Greedy-algorithm-of-verfication-InOrder">this wiki page</a>. 2515 * <p> 2516 * As of Mockito 1.8.4 you can verifyNoMoreInvocations() in order-sensitive way. Read more: {@link InOrder#verifyNoMoreInteractions()} 2517 * <p> 2518 * See examples in javadoc for {@link Mockito} class 2519 * 2520 * @param mocks to be verified in order 2521 * 2522 * @return InOrder object to be used to verify in order 2523 */ 2524 public static InOrder inOrder(Object... mocks) { 2525 return MOCKITO_CORE.inOrder(mocks); 2526 } 2527 2528 /** 2529 * Ignores stubbed methods of given mocks for the sake of verification. 2530 * Sometimes useful when coupled with <code>verifyNoMoreInteractions()</code> or verification <code>inOrder()</code>. 2531 * Helps avoiding redundant verification of stubbed calls - typically we're not interested in verifying stubs. 2532 * <p> 2533 * <b>Warning</b>, <code>ignoreStubs()</code> might lead to overuse of <code>verifyNoMoreInteractions(ignoreStubs(...));</code> 2534 * Bear in mind that Mockito does not recommend bombarding every test with <code>verifyNoMoreInteractions()</code> 2535 * for the reasons outlined in javadoc for {@link Mockito#verifyNoMoreInteractions(Object...)} 2536 * Other words: all <b>*stubbed*</b> methods of given mocks are marked <b>*verified*</b> so that they don't get in a way during verifyNoMoreInteractions(). 2537 * <p> 2538 * This method <b>changes the input mocks</b>! This method returns input mocks just for convenience. 2539 * <p> 2540 * Ignored stubs will also be ignored for verification inOrder, including {@link org.mockito.InOrder#verifyNoMoreInteractions()}. 2541 * See the second example. 2542 * <p> 2543 * Example: 2544 * <pre class="code"><code class="java"> 2545 * //mocking lists for the sake of the example (if you mock List in real you will burn in hell) 2546 * List mock1 = mock(List.class), mock2 = mock(List.class); 2547 * 2548 * //stubbing mocks: 2549 * when(mock1.get(0)).thenReturn(10); 2550 * when(mock2.get(0)).thenReturn(20); 2551 * 2552 * //using mocks by calling stubbed get(0) methods: 2553 * System.out.println(mock1.get(0)); //prints 10 2554 * System.out.println(mock2.get(0)); //prints 20 2555 * 2556 * //using mocks by calling clear() methods: 2557 * mock1.clear(); 2558 * mock2.clear(); 2559 * 2560 * //verification: 2561 * verify(mock1).clear(); 2562 * verify(mock2).clear(); 2563 * 2564 * //verifyNoMoreInteractions() fails because get() methods were not accounted for. 2565 * try { verifyNoMoreInteractions(mock1, mock2); } catch (NoInteractionsWanted e); 2566 * 2567 * //However, if we ignore stubbed methods then we can verifyNoMoreInteractions() 2568 * verifyNoMoreInteractions(ignoreStubs(mock1, mock2)); 2569 * 2570 * //Remember that ignoreStubs() <b>*changes*</b> the input mocks and returns them for convenience. 2571 * </code></pre> 2572 * Ignoring stubs can be used with <b>verification in order</b>: 2573 * <pre class="code"><code class="java"> 2574 * List list = mock(List.class); 2575 * when(mock.get(0)).thenReturn("foo"); 2576 * 2577 * list.add(0); 2578 * System.out.println(list.get(0)); //we don't want to verify this 2579 * list.clear(); 2580 * 2581 * InOrder inOrder = inOrder(ignoreStubs(list)); 2582 * inOrder.verify(list).add(0); 2583 * inOrder.verify(list).clear(); 2584 * inOrder.verifyNoMoreInteractions(); 2585 * </code></pre> 2586 * 2587 * @since 1.9.0 2588 * @param mocks input mocks that will be changed 2589 * @return the same mocks that were passed in as parameters 2590 */ 2591 public static Object[] ignoreStubs(Object... mocks) { 2592 return MOCKITO_CORE.ignoreStubs(mocks); 2593 } 2594 2595 /** 2596 * Allows verifying exact number of invocations. E.g: 2597 * <pre class="code"><code class="java"> 2598 * verify(mock, times(2)).someMethod("some arg"); 2599 * </code></pre> 2600 * 2601 * See examples in javadoc for {@link Mockito} class 2602 * 2603 * @param wantedNumberOfInvocations wanted number of invocations 2604 * 2605 * @return verification mode 2606 */ 2607 public static VerificationMode times(int wantedNumberOfInvocations) { 2608 return VerificationModeFactory.times(wantedNumberOfInvocations); 2609 } 2610 2611 /** 2612 * Alias to <code>times(0)</code>, see {@link Mockito#times(int)} 2613 * <p> 2614 * Verifies that interaction did not happen. E.g: 2615 * <pre class="code"><code class="java"> 2616 * verify(mock, never()).someMethod(); 2617 * </code></pre> 2618 * 2619 * <p> 2620 * If you want to verify there were NO interactions with the mock 2621 * check out {@link Mockito#verifyZeroInteractions(Object...)} 2622 * or {@link Mockito#verifyNoMoreInteractions(Object...)} 2623 * <p> 2624 * See examples in javadoc for {@link Mockito} class 2625 * 2626 * @return verification mode 2627 */ 2628 public static VerificationMode never() { 2629 return times(0); 2630 } 2631 2632 /** 2633 * Allows at-least-once verification. E.g: 2634 * <pre class="code"><code class="java"> 2635 * verify(mock, atLeastOnce()).someMethod("some arg"); 2636 * </code></pre> 2637 * Alias to <code>atLeast(1)</code>. 2638 * <p> 2639 * See examples in javadoc for {@link Mockito} class 2640 * 2641 * @return verification mode 2642 */ 2643 public static VerificationMode atLeastOnce() { 2644 return VerificationModeFactory.atLeastOnce(); 2645 } 2646 2647 /** 2648 * Allows at-least-x verification. E.g: 2649 * <pre class="code"><code class="java"> 2650 * verify(mock, atLeast(3)).someMethod("some arg"); 2651 * </code></pre> 2652 * 2653 * See examples in javadoc for {@link Mockito} class 2654 * 2655 * @param minNumberOfInvocations minimum number of invocations 2656 * 2657 * @return verification mode 2658 */ 2659 public static VerificationMode atLeast(int minNumberOfInvocations) { 2660 return VerificationModeFactory.atLeast(minNumberOfInvocations); 2661 } 2662 2663 /** 2664 * Allows at-most-x verification. E.g: 2665 * <pre class="code"><code class="java"> 2666 * verify(mock, atMost(3)).someMethod("some arg"); 2667 * </code></pre> 2668 * 2669 * See examples in javadoc for {@link Mockito} class 2670 * 2671 * @param maxNumberOfInvocations max number of invocations 2672 * 2673 * @return verification mode 2674 */ 2675 public static VerificationMode atMost(int maxNumberOfInvocations) { 2676 return VerificationModeFactory.atMost(maxNumberOfInvocations); 2677 } 2678 2679 /** 2680 * Allows non-greedy verification in order. For example 2681 * <pre class="code"><code class="java"> 2682 * inOrder.verify( mock, calls( 2 )).someMethod( "some arg" ); 2683 * </code></pre> 2684 * <ul> 2685 * <li>will not fail if the method is called 3 times, unlike times( 2 )</li> 2686 * <li>will not mark the third invocation as verified, unlike atLeast( 2 )</li> 2687 * </ul> 2688 * This verification mode can only be used with in order verification. 2689 * @param wantedNumberOfInvocations number of invocations to verify 2690 * @return verification mode 2691 */ 2692 public static VerificationMode calls( int wantedNumberOfInvocations ){ 2693 return VerificationModeFactory.calls( wantedNumberOfInvocations ); 2694 } 2695 2696 /** 2697 * Allows checking if given method was the only one invoked. E.g: 2698 * <pre class="code"><code class="java"> 2699 * verify(mock, only()).someMethod(); 2700 * //above is a shorthand for following 2 lines of code: 2701 * verify(mock).someMethod(); 2702 * verifyNoMoreInvocations(mock); 2703 * </code></pre> 2704 * 2705 * <p> 2706 * See also {@link Mockito#verifyNoMoreInteractions(Object...)} 2707 * <p> 2708 * See examples in javadoc for {@link Mockito} class 2709 * 2710 * @return verification mode 2711 */ 2712 public static VerificationMode only() { 2713 return VerificationModeFactory.only(); 2714 } 2715 2716 /** 2717 * Allows verifying with timeout. It causes a verify to wait for a specified period of time for a desired 2718 * interaction rather than fails immediately if has not already happened. May be useful for testing in concurrent 2719 * conditions. 2720 * <p> 2721 * This differs from {@link Mockito#after after()} in that after() will wait the full period, unless 2722 * the final test result is known early (e.g. if a never() fails), whereas timeout() will stop early as soon 2723 * as verification passes, producing different behaviour when used with times(2), for example, which can pass 2724 * and then later fail. In that case, timeout would pass as soon as times(2) passes, whereas after would run until 2725 * times(2) failed, and then fail. 2726 * <p> 2727 * This feature should be used rarely - figure out a better way of testing your multi-threaded system. 2728 * <pre class="code"><code class="java"> 2729 * //passes when someMethod() is called within given time span 2730 * verify(mock, timeout(100)).someMethod(); 2731 * //above is an alias to: 2732 * verify(mock, timeout(100).times(1)).someMethod(); 2733 * 2734 * //passes as soon as someMethod() has been called 2 times before the given timeout 2735 * verify(mock, timeout(100).times(2)).someMethod(); 2736 * 2737 * //equivalent: this also passes as soon as someMethod() has been called 2 times before the given timeout 2738 * verify(mock, timeout(100).atLeast(2)).someMethod(); 2739 * 2740 * //verifies someMethod() within given time span using given verification mode 2741 * //useful only if you have your own custom verification modes. 2742 * verify(mock, new Timeout(100, yourOwnVerificationMode)).someMethod(); 2743 * </code></pre> 2744 * 2745 * See examples in javadoc for {@link Mockito} class 2746 * 2747 * @param millis - time span in milliseconds 2748 * 2749 * @return verification mode 2750 */ 2751 public static VerificationWithTimeout timeout(long millis) { 2752 return new Timeout(millis, VerificationModeFactory.times(1)); 2753 } 2754 2755 /** 2756 * Allows verifying over a given period. It causes a verify to wait for a specified period of time for a desired 2757 * interaction rather than failing immediately if has not already happened. May be useful for testing in concurrent 2758 * conditions. 2759 * <p> 2760 * This differs from {@link Mockito#timeout timeout()} in that after() will wait the full period, whereas timeout() 2761 * will stop early as soon as verification passes, producing different behaviour when used with times(2), for example, 2762 * which can pass and then later fail. In that case, timeout would pass as soon as times(2) passes, whereas after would 2763 * run the full time, which point it will fail, as times(2) has failed. 2764 * <p> 2765 * This feature should be used rarely - figure out a better way of testing your multi-threaded system. 2766 * <p> 2767 * Not yet implemented to work with InOrder verification. 2768 * <pre class="code"><code class="java"> 2769 * //passes after 100ms, if someMethod() has only been called once at that time. 2770 * verify(mock, after(100)).someMethod(); 2771 * //above is an alias to: 2772 * verify(mock, after(100).times(1)).someMethod(); 2773 * 2774 * //passes if someMethod() is called <b>*exactly*</b> 2 times after the given timespan 2775 * verify(mock, after(100).times(2)).someMethod(); 2776 * 2777 * //passes if someMethod() has not been called after the given timespan 2778 * verify(mock, after(100).never()).someMethod(); 2779 * 2780 * //verifies someMethod() after a given time span using given verification mode 2781 * //useful only if you have your own custom verification modes. 2782 * verify(mock, new After(100, yourOwnVerificationMode)).someMethod(); 2783 * </code></pre> 2784 * 2785 * See examples in javadoc for {@link Mockito} class 2786 * 2787 * @param millis - time span in milliseconds 2788 * 2789 * @return verification mode 2790 */ 2791 public static VerificationAfterDelay after(long millis) { 2792 return new After(millis, VerificationModeFactory.times(1)); 2793 } 2794 2795 /** 2796 * First of all, in case of any trouble, I encourage you to read the Mockito FAQ: <a href="https://github.com/mockito/mockito/wiki/FAQ">https://github.com/mockito/mockito/wiki/FAQ</a> 2797 * <p> 2798 * In case of questions you may also post to mockito mailing list: <a href="http://groups.google.com/group/mockito">http://groups.google.com/group/mockito</a> 2799 * <p> 2800 * <code>validateMockitoUsage()</code> <b>explicitly validates</b> the framework state to detect invalid use of Mockito. 2801 * However, this feature is optional <b>because Mockito validates the usage all the time...</b> but there is a gotcha so read on. 2802 * <p> 2803 * Examples of incorrect use: 2804 * <pre class="code"><code class="java"> 2805 * //Oops, thenReturn() part is missing: 2806 * when(mock.get()); 2807 * 2808 * //Oops, verified method call is inside verify() where it should be on the outside: 2809 * verify(mock.execute()); 2810 * 2811 * //Oops, missing method to verify: 2812 * verify(mock); 2813 * </code></pre> 2814 * 2815 * Mockito throws exceptions if you misuse it so that you know if your tests are written correctly. 2816 * The gotcha is that Mockito does the validation <b>next time</b> you use the framework (e.g. next time you verify, stub, call mock etc.). 2817 * But even though the exception might be thrown in the next test, 2818 * the exception <b>message contains a navigable stack trace element</b> with location of the defect. 2819 * Hence you can click and find the place where Mockito was misused. 2820 * <p> 2821 * Sometimes though, you might want to validate the framework usage explicitly. 2822 * For example, one of the users wanted to put <code>validateMockitoUsage()</code> in his <code>@After</code> method 2823 * so that he knows immediately when he misused Mockito. 2824 * Without it, he would have known about it not sooner than <b>next time</b> he used the framework. 2825 * One more benefit of having <code>validateMockitoUsage()</code> in <code>@After</code> is that jUnit runner and rule will always fail in the test method with defect 2826 * whereas ordinary 'next-time' validation might fail the <b>next</b> test method. 2827 * But even though JUnit might report next test as red, don't worry about it 2828 * and just click at navigable stack trace element in the exception message to instantly locate the place where you misused mockito. 2829 * <p> 2830 * <b>Both built-in runner: {@link MockitoJUnitRunner} and rule: {@link MockitoRule}</b> do validateMockitoUsage() after each test method. 2831 * <p> 2832 * Bear in mind that <b>usually you don't have to <code>validateMockitoUsage()</code></b> 2833 * and framework validation triggered on next-time basis should be just enough, 2834 * mainly because of enhanced exception message with clickable location of defect. 2835 * However, I would recommend validateMockitoUsage() if you already have sufficient test infrastructure 2836 * (like your own runner or base class for all tests) because adding a special action to <code>@After</code> has zero cost. 2837 * <p> 2838 * See examples in javadoc for {@link Mockito} class 2839 */ 2840 public static void validateMockitoUsage() { 2841 MOCKITO_CORE.validateMockitoUsage(); 2842 } 2843 2844 /** 2845 * Allows mock creation with additional mock settings. 2846 * <p> 2847 * Don't use it too often. 2848 * Consider writing simple tests that use simple mocks. 2849 * Repeat after me: simple tests push simple, KISSy, readable & maintainable code. 2850 * If you cannot write a test in a simple way - refactor the code under test. 2851 * <p> 2852 * Examples of mock settings: 2853 * <pre class="code"><code class="java"> 2854 * //Creates mock with different default answer & name 2855 * Foo mock = mock(Foo.class, withSettings() 2856 * .defaultAnswer(RETURNS_SMART_NULLS) 2857 * .name("cool mockie")); 2858 * 2859 * //Creates mock with different default answer, descriptive name and extra interfaces 2860 * Foo mock = mock(Foo.class, withSettings() 2861 * .defaultAnswer(RETURNS_SMART_NULLS) 2862 * .name("cool mockie") 2863 * .extraInterfaces(Bar.class)); 2864 * </code></pre> 2865 * {@link MockSettings} has been introduced for two reasons. 2866 * Firstly, to make it easy to add another mock settings when the demand comes. 2867 * Secondly, to enable combining different mock settings without introducing zillions of overloaded mock() methods. 2868 * <p> 2869 * See javadoc for {@link MockSettings} to learn about possible mock settings. 2870 * <p> 2871 * 2872 * @return mock settings instance with defaults. 2873 */ 2874 public static MockSettings withSettings() { 2875 return new MockSettingsImpl().defaultAnswer(RETURNS_DEFAULTS); 2876 } 2877 2878 /** 2879 * Adds a description to be printed if verification fails. 2880 * <pre class="code"><code class="java"> 2881 * verify(mock, description("This will print on failure")).someMethod("some arg"); 2882 * </code></pre> 2883 * @param description The description to print on failure. 2884 * @return verification mode 2885 * @since 2.1.0 2886 */ 2887 public static VerificationMode description(String description) { 2888 return times(1).description(description); 2889 } 2890 2891 /** 2892 * @deprecated - please use {@link MockingDetails#printInvocations()} instead. 2893 * An instance of {@code MockingDetails} can be retrieved via {@link #mockingDetails(Object)}. 2894 */ 2895 @Deprecated 2896 static MockitoDebugger debug() { 2897 return new MockitoDebuggerImpl(); 2898 } 2899 2900 /** 2901 * For advanced users or framework integrators. See {@link MockitoFramework} class. 2902 * 2903 * @since 2.1.0 2904 */ 2905 @Incubating 2906 public static MockitoFramework framework() { 2907 return new DefaultMockitoFramework(); 2908 } 2909 2910 /** 2911 * {@code MockitoSession} is an optional, highly recommended feature 2912 * that helps driving cleaner tests by eliminating boilerplate code and adding extra validation. 2913 * <p> 2914 * For more information, including use cases and sample code, see the javadoc for {@link MockitoSession}. 2915 * 2916 * @since 2.7.0 2917 */ 2918 @Incubating 2919 public static MockitoSessionBuilder mockitoSession() { 2920 return new DefaultMockitoSessionBuilder(); 2921 } 2922} 2923