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29//
30// Author: wan@google.com (Zhanyong Wan)
31
32// This sample shows how to test common properties of multiple
33// implementations of the same interface (aka interface tests).
34
35// The interface and its implementations are in this header.
36#include "prime_tables.h"
37
38#include <gtest/gtest.h>
39
40// First, we define some factory functions for creating instances of
41// the implementations.  You may be able to skip this step if all your
42// implementations can be constructed the same way.
43
44template <class T>
45PrimeTable* CreatePrimeTable();
46
47template <>
48PrimeTable* CreatePrimeTable<OnTheFlyPrimeTable>() {
49  return new OnTheFlyPrimeTable;
50}
51
52template <>
53PrimeTable* CreatePrimeTable<PreCalculatedPrimeTable>() {
54  return new PreCalculatedPrimeTable(10000);
55}
56
57// Then we define a test fixture class template.
58template <class T>
59class PrimeTableTest : public testing::Test {
60 protected:
61  // The ctor calls the factory function to create a prime table
62  // implemented by T.
63  PrimeTableTest() : table_(CreatePrimeTable<T>()) {}
64
65  virtual ~PrimeTableTest() { delete table_; }
66
67  // Note that we test an implementation via the base interface
68  // instead of the actual implementation class.  This is important
69  // for keeping the tests close to the real world scenario, where the
70  // implementation is invoked via the base interface.  It avoids
71  // got-yas where the implementation class has a method that shadows
72  // a method with the same name (but slightly different argument
73  // types) in the base interface, for example.
74  PrimeTable* const table_;
75};
76
77#if GTEST_HAS_TYPED_TEST
78
79using testing::Types;
80
81// Google Test offers two ways for reusing tests for different types.
82// The first is called "typed tests".  You should use it if you
83// already know *all* the types you are gonna exercise when you write
84// the tests.
85
86// To write a typed test case, first use
87//
88//   TYPED_TEST_CASE(TestCaseName, TypeList);
89//
90// to declare it and specify the type parameters.  As with TEST_F,
91// TestCaseName must match the test fixture name.
92
93// The list of types we want to test.
94typedef Types<OnTheFlyPrimeTable, PreCalculatedPrimeTable> Implementations;
95
96TYPED_TEST_CASE(PrimeTableTest, Implementations);
97
98// Then use TYPED_TEST(TestCaseName, TestName) to define a typed test,
99// similar to TEST_F.
100TYPED_TEST(PrimeTableTest, ReturnsFalseForNonPrimes) {
101  // Inside the test body, you can refer to the type parameter by
102  // TypeParam, and refer to the fixture class by TestFixture.  We
103  // don't need them in this example.
104
105  // Since we are in the template world, C++ requires explicitly
106  // writing 'this->' when referring to members of the fixture class.
107  // This is something you have to learn to live with.
108  EXPECT_FALSE(this->table_->IsPrime(-5));
109  EXPECT_FALSE(this->table_->IsPrime(0));
110  EXPECT_FALSE(this->table_->IsPrime(1));
111  EXPECT_FALSE(this->table_->IsPrime(4));
112  EXPECT_FALSE(this->table_->IsPrime(6));
113  EXPECT_FALSE(this->table_->IsPrime(100));
114}
115
116TYPED_TEST(PrimeTableTest, ReturnsTrueForPrimes) {
117  EXPECT_TRUE(this->table_->IsPrime(2));
118  EXPECT_TRUE(this->table_->IsPrime(3));
119  EXPECT_TRUE(this->table_->IsPrime(5));
120  EXPECT_TRUE(this->table_->IsPrime(7));
121  EXPECT_TRUE(this->table_->IsPrime(11));
122  EXPECT_TRUE(this->table_->IsPrime(131));
123}
124
125TYPED_TEST(PrimeTableTest, CanGetNextPrime) {
126  EXPECT_EQ(2, this->table_->GetNextPrime(0));
127  EXPECT_EQ(3, this->table_->GetNextPrime(2));
128  EXPECT_EQ(5, this->table_->GetNextPrime(3));
129  EXPECT_EQ(7, this->table_->GetNextPrime(5));
130  EXPECT_EQ(11, this->table_->GetNextPrime(7));
131  EXPECT_EQ(131, this->table_->GetNextPrime(128));
132}
133
134// That's it!  Google Test will repeat each TYPED_TEST for each type
135// in the type list specified in TYPED_TEST_CASE.  Sit back and be
136// happy that you don't have to define them multiple times.
137
138#endif  // GTEST_HAS_TYPED_TEST
139
140#if GTEST_HAS_TYPED_TEST_P
141
142using testing::Types;
143
144// Sometimes, however, you don't yet know all the types that you want
145// to test when you write the tests.  For example, if you are the
146// author of an interface and expect other people to implement it, you
147// might want to write a set of tests to make sure each implementation
148// conforms to some basic requirements, but you don't know what
149// implementations will be written in the future.
150//
151// How can you write the tests without committing to the type
152// parameters?  That's what "type-parameterized tests" can do for you.
153// It is a bit more involved than typed tests, but in return you get a
154// test pattern that can be reused in many contexts, which is a big
155// win.  Here's how you do it:
156
157// First, define a test fixture class template.  Here we just reuse
158// the PrimeTableTest fixture defined earlier:
159
160template <class T>
161class PrimeTableTest2 : public PrimeTableTest<T> {
162};
163
164// Then, declare the test case.  The argument is the name of the test
165// fixture, and also the name of the test case (as usual).  The _P
166// suffix is for "parameterized" or "pattern".
167TYPED_TEST_CASE_P(PrimeTableTest2);
168
169// Next, use TYPED_TEST_P(TestCaseName, TestName) to define a test,
170// similar to what you do with TEST_F.
171TYPED_TEST_P(PrimeTableTest2, ReturnsFalseForNonPrimes) {
172  EXPECT_FALSE(this->table_->IsPrime(-5));
173  EXPECT_FALSE(this->table_->IsPrime(0));
174  EXPECT_FALSE(this->table_->IsPrime(1));
175  EXPECT_FALSE(this->table_->IsPrime(4));
176  EXPECT_FALSE(this->table_->IsPrime(6));
177  EXPECT_FALSE(this->table_->IsPrime(100));
178}
179
180TYPED_TEST_P(PrimeTableTest2, ReturnsTrueForPrimes) {
181  EXPECT_TRUE(this->table_->IsPrime(2));
182  EXPECT_TRUE(this->table_->IsPrime(3));
183  EXPECT_TRUE(this->table_->IsPrime(5));
184  EXPECT_TRUE(this->table_->IsPrime(7));
185  EXPECT_TRUE(this->table_->IsPrime(11));
186  EXPECT_TRUE(this->table_->IsPrime(131));
187}
188
189TYPED_TEST_P(PrimeTableTest2, CanGetNextPrime) {
190  EXPECT_EQ(2, this->table_->GetNextPrime(0));
191  EXPECT_EQ(3, this->table_->GetNextPrime(2));
192  EXPECT_EQ(5, this->table_->GetNextPrime(3));
193  EXPECT_EQ(7, this->table_->GetNextPrime(5));
194  EXPECT_EQ(11, this->table_->GetNextPrime(7));
195  EXPECT_EQ(131, this->table_->GetNextPrime(128));
196}
197
198// Type-parameterized tests involve one extra step: you have to
199// enumerate the tests you defined:
200REGISTER_TYPED_TEST_CASE_P(
201    PrimeTableTest2,  // The first argument is the test case name.
202    // The rest of the arguments are the test names.
203    ReturnsFalseForNonPrimes, ReturnsTrueForPrimes, CanGetNextPrime);
204
205// At this point the test pattern is done.  However, you don't have
206// any real test yet as you haven't said which types you want to run
207// the tests with.
208
209// To turn the abstract test pattern into real tests, you instantiate
210// it with a list of types.  Usually the test pattern will be defined
211// in a .h file, and anyone can #include and instantiate it.  You can
212// even instantiate it more than once in the same program.  To tell
213// different instances apart, you give each of them a name, which will
214// become part of the test case name and can be used in test filters.
215
216// The list of types we want to test.  Note that it doesn't have to be
217// defined at the time we write the TYPED_TEST_P()s.
218typedef Types<OnTheFlyPrimeTable, PreCalculatedPrimeTable>
219    PrimeTableImplementations;
220INSTANTIATE_TYPED_TEST_CASE_P(OnTheFlyAndPreCalculated,    // Instance name
221                              PrimeTableTest2,             // Test case name
222                              PrimeTableImplementations);  // Type list
223
224#endif  // GTEST_HAS_TYPED_TEST_P
225