/* * Copyright (c) 2007 Mockito contributors * This program is made available under the terms of the MIT License. */ package org.mockito; import org.hamcrest.BaseMatcher; import org.hamcrest.Description; import org.hamcrest.Matcher; import org.mockito.internal.util.Decamelizer; /** * Allows creating customized argument matchers. *
* ArgumentMatcher is an hamcrest {@link Matcher} with predefined describeTo() method. * In case of failure, ArgumentMatcher generates description based on decamelized class name - to promote meaningful class names. * For example StringWithStrongLanguage matcher will generate 'String with strong language' description. * You can always override describeTo() method and provide detailed description. *
* Use {@link Matchers#argThat} method and pass an instance of hamcrest {@link Matcher}, e.g: * *
* class IsListOfTwoElements extends ArgumentMatcher<List> {
* public boolean matches(Object list) {
* return ((List) list).size() == 2;
* }
* }
*
* List mock = mock(List.class);
*
* when(mock.addAll(argThat(new IsListOfTwoElements()))).thenReturn(true);
*
* mock.addAll(Arrays.asList("one", "two"));
*
* verify(mock).addAll(argThat(new IsListOfTwoElements()));
*
*
* To keep it readable you may want to extract method, e.g:
*
*
* verify(mock).addAll(argThat(new IsListOfTwoElements()));
* //becomes
* verify(mock).addAll(listOfTwoElements());
*
*
* Warning: Be reasonable with using complicated argument matching, especially custom argument matchers, as it can make the test less readable.
* Sometimes it's better to implement equals() for arguments that are passed to mocks
* (Mockito naturally uses equals() for argument matching).
* This can make the test cleaner.
* * Also, sometimes {@link ArgumentCaptor} may be a better fit than custom matcher. * For example, if custom argument matcher is not likely to be reused * or you just need it to assert on argument values to complete verification of behavior. *
* Read more about other matchers in javadoc for {@link Matchers} class
*
* @param
* The method should never assert if the argument doesn't match. It
* should only return false.
*
* @param argument
* the argument
* @return whether this matcher accepts the given argument.
*/
public abstract boolean matches(Object argument);
/**
* By default this method decamelizes matchers name to promote meaningful names for matchers.
*
* For example StringWithStrongLanguage matcher will generate 'String with strong language' description in case of failure.
*
* You might want to override this method to
* provide more specific description of the matcher (useful when
* verification failures are reported).
*
* @param description the description to which the matcher description is
* appended.
*/
public void describeTo(Description description) {
String className = getClass().getSimpleName();
description.appendText(Decamelizer.decamelizeMatcher(className));
}
}