1 // Copyright 2008 Google Inc. 2 // All Rights Reserved. 3 // 4 // Redistribution and use in source and binary forms, with or without 5 // modification, are permitted provided that the following conditions are 6 // met: 7 // 8 // * Redistributions of source code must retain the above copyright 9 // notice, this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above 11 // copyright notice, this list of conditions and the following disclaimer 12 // in the documentation and/or other materials provided with the 13 // distribution. 14 // * Neither the name of Google Inc. nor the names of its 15 // contributors may be used to endorse or promote products derived from 16 // this software without specific prior written permission. 17 // 18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30 // This sample shows how to test common properties of multiple 31 // implementations of the same interface (aka interface tests). 32 33 // The interface and its implementations are in this header. 34 #include "prime_tables.h" 35 #include "gtest/gtest.h" 36 namespace { 37 // First, we define some factory functions for creating instances of 38 // the implementations. You may be able to skip this step if all your 39 // implementations can be constructed the same way. 40 41 template <class T> 42 PrimeTable* CreatePrimeTable(); 43 44 template <> 45 PrimeTable* CreatePrimeTable<OnTheFlyPrimeTable>() { 46 return new OnTheFlyPrimeTable; 47 } 48 49 template <> 50 PrimeTable* CreatePrimeTable<PreCalculatedPrimeTable>() { 51 return new PreCalculatedPrimeTable(10000); 52 } 53 54 // Then we define a test fixture class template. 55 template <class T> 56 class PrimeTableTest : public testing::Test { 57 protected: 58 // The ctor calls the factory function to create a prime table 59 // implemented by T. 60 PrimeTableTest() : table_(CreatePrimeTable<T>()) {} 61 62 ~PrimeTableTest() override { delete table_; } 63 64 // Note that we test an implementation via the base interface 65 // instead of the actual implementation class. This is important 66 // for keeping the tests close to the real world scenario, where the 67 // implementation is invoked via the base interface. It avoids 68 // got-yas where the implementation class has a method that shadows 69 // a method with the same name (but slightly different argument 70 // types) in the base interface, for example. 71 PrimeTable* const table_; 72 }; 73 74 using testing::Types; 75 76 // Google Test offers two ways for reusing tests for different types. 77 // The first is called "typed tests". You should use it if you 78 // already know *all* the types you are gonna exercise when you write 79 // the tests. 80 81 // To write a typed test case, first use 82 // 83 // TYPED_TEST_SUITE(TestCaseName, TypeList); 84 // 85 // to declare it and specify the type parameters. As with TEST_F, 86 // TestCaseName must match the test fixture name. 87 88 // The list of types we want to test. 89 typedef Types<OnTheFlyPrimeTable, PreCalculatedPrimeTable> Implementations; 90 91 TYPED_TEST_SUITE(PrimeTableTest, Implementations); 92 93 // Then use TYPED_TEST(TestCaseName, TestName) to define a typed test, 94 // similar to TEST_F. 95 TYPED_TEST(PrimeTableTest, ReturnsFalseForNonPrimes) { 96 // Inside the test body, you can refer to the type parameter by 97 // TypeParam, and refer to the fixture class by TestFixture. We 98 // don't need them in this example. 99 100 // Since we are in the template world, C++ requires explicitly 101 // writing 'this->' when referring to members of the fixture class. 102 // This is something you have to learn to live with. 103 EXPECT_FALSE(this->table_->IsPrime(-5)); 104 EXPECT_FALSE(this->table_->IsPrime(0)); 105 EXPECT_FALSE(this->table_->IsPrime(1)); 106 EXPECT_FALSE(this->table_->IsPrime(4)); 107 EXPECT_FALSE(this->table_->IsPrime(6)); 108 EXPECT_FALSE(this->table_->IsPrime(100)); 109 } 110 111 TYPED_TEST(PrimeTableTest, ReturnsTrueForPrimes) { 112 EXPECT_TRUE(this->table_->IsPrime(2)); 113 EXPECT_TRUE(this->table_->IsPrime(3)); 114 EXPECT_TRUE(this->table_->IsPrime(5)); 115 EXPECT_TRUE(this->table_->IsPrime(7)); 116 EXPECT_TRUE(this->table_->IsPrime(11)); 117 EXPECT_TRUE(this->table_->IsPrime(131)); 118 } 119 120 TYPED_TEST(PrimeTableTest, CanGetNextPrime) { 121 EXPECT_EQ(2, this->table_->GetNextPrime(0)); 122 EXPECT_EQ(3, this->table_->GetNextPrime(2)); 123 EXPECT_EQ(5, this->table_->GetNextPrime(3)); 124 EXPECT_EQ(7, this->table_->GetNextPrime(5)); 125 EXPECT_EQ(11, this->table_->GetNextPrime(7)); 126 EXPECT_EQ(131, this->table_->GetNextPrime(128)); 127 } 128 129 // That's it! Google Test will repeat each TYPED_TEST for each type 130 // in the type list specified in TYPED_TEST_SUITE. Sit back and be 131 // happy that you don't have to define them multiple times. 132 133 using testing::Types; 134 135 // Sometimes, however, you don't yet know all the types that you want 136 // to test when you write the tests. For example, if you are the 137 // author of an interface and expect other people to implement it, you 138 // might want to write a set of tests to make sure each implementation 139 // conforms to some basic requirements, but you don't know what 140 // implementations will be written in the future. 141 // 142 // How can you write the tests without committing to the type 143 // parameters? That's what "type-parameterized tests" can do for you. 144 // It is a bit more involved than typed tests, but in return you get a 145 // test pattern that can be reused in many contexts, which is a big 146 // win. Here's how you do it: 147 148 // First, define a test fixture class template. Here we just reuse 149 // the PrimeTableTest fixture defined earlier: 150 151 template <class T> 152 class PrimeTableTest2 : public PrimeTableTest<T> {}; 153 154 // Then, declare the test case. The argument is the name of the test 155 // fixture, and also the name of the test case (as usual). The _P 156 // suffix is for "parameterized" or "pattern". 157 TYPED_TEST_SUITE_P(PrimeTableTest2); 158 159 // Next, use TYPED_TEST_P(TestCaseName, TestName) to define a test, 160 // similar to what you do with TEST_F. 161 TYPED_TEST_P(PrimeTableTest2, ReturnsFalseForNonPrimes) { 162 EXPECT_FALSE(this->table_->IsPrime(-5)); 163 EXPECT_FALSE(this->table_->IsPrime(0)); 164 EXPECT_FALSE(this->table_->IsPrime(1)); 165 EXPECT_FALSE(this->table_->IsPrime(4)); 166 EXPECT_FALSE(this->table_->IsPrime(6)); 167 EXPECT_FALSE(this->table_->IsPrime(100)); 168 } 169 170 TYPED_TEST_P(PrimeTableTest2, ReturnsTrueForPrimes) { 171 EXPECT_TRUE(this->table_->IsPrime(2)); 172 EXPECT_TRUE(this->table_->IsPrime(3)); 173 EXPECT_TRUE(this->table_->IsPrime(5)); 174 EXPECT_TRUE(this->table_->IsPrime(7)); 175 EXPECT_TRUE(this->table_->IsPrime(11)); 176 EXPECT_TRUE(this->table_->IsPrime(131)); 177 } 178 179 TYPED_TEST_P(PrimeTableTest2, CanGetNextPrime) { 180 EXPECT_EQ(2, this->table_->GetNextPrime(0)); 181 EXPECT_EQ(3, this->table_->GetNextPrime(2)); 182 EXPECT_EQ(5, this->table_->GetNextPrime(3)); 183 EXPECT_EQ(7, this->table_->GetNextPrime(5)); 184 EXPECT_EQ(11, this->table_->GetNextPrime(7)); 185 EXPECT_EQ(131, this->table_->GetNextPrime(128)); 186 } 187 188 // Type-parameterized tests involve one extra step: you have to 189 // enumerate the tests you defined: 190 REGISTER_TYPED_TEST_SUITE_P( 191 PrimeTableTest2, // The first argument is the test case name. 192 // The rest of the arguments are the test names. 193 ReturnsFalseForNonPrimes, ReturnsTrueForPrimes, CanGetNextPrime); 194 195 // At this point the test pattern is done. However, you don't have 196 // any real test yet as you haven't said which types you want to run 197 // the tests with. 198 199 // To turn the abstract test pattern into real tests, you instantiate 200 // it with a list of types. Usually the test pattern will be defined 201 // in a .h file, and anyone can #include and instantiate it. You can 202 // even instantiate it more than once in the same program. To tell 203 // different instances apart, you give each of them a name, which will 204 // become part of the test case name and can be used in test filters. 205 206 // The list of types we want to test. Note that it doesn't have to be 207 // defined at the time we write the TYPED_TEST_P()s. 208 typedef Types<OnTheFlyPrimeTable, PreCalculatedPrimeTable> 209 PrimeTableImplementations; 210 INSTANTIATE_TYPED_TEST_SUITE_P(OnTheFlyAndPreCalculated, // Instance name 211 PrimeTableTest2, // Test case name 212 PrimeTableImplementations); // Type list 213 214 } // namespace 215