// Copyright 2008 Google Inc.
// All Rights Reserved.
//
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// modification, are permitted provided that the following conditions are
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//
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// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
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//
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// This sample shows how to test common properties of multiple
// implementations of the same interface (aka interface tests).
// The interface and its implementations are in this header.
#include "prime_tables.h"
#include "gtest/gtest.h"
namespace {
// First, we define some factory functions for creating instances of
// the implementations. You may be able to skip this step if all your
// implementations can be constructed the same way.
template <class T>
PrimeTable* CreatePrimeTable();
template <>
PrimeTable* CreatePrimeTable<OnTheFlyPrimeTable>() {
return new OnTheFlyPrimeTable;
}
template <>
PrimeTable* CreatePrimeTable<PreCalculatedPrimeTable>() {
return new PreCalculatedPrimeTable(10000);
}
// Then we define a test fixture class template.
template <class T>
class PrimeTableTest : public testing::Test {
protected:
// The ctor calls the factory function to create a prime table
// implemented by T.
PrimeTableTest() : table_(CreatePrimeTable<T>()) {}
virtual ~PrimeTableTest() { delete table_; }
// Note that we test an implementation via the base interface
// instead of the actual implementation class. This is important
// for keeping the tests close to the real world scenario, where the
// implementation is invoked via the base interface. It avoids
// got-yas where the implementation class has a method that shadows
// a method with the same name (but slightly different argument
// types) in the base interface, for example.
PrimeTable* const table_;
};
#if GTEST_HAS_TYPED_TEST
using testing::Types;
// Google Test offers two ways for reusing tests for different types.
// The first is called "typed tests". You should use it if you
// already know *all* the types you are gonna exercise when you write
// the tests.
// To write a typed test case, first use
//
// TYPED_TEST_CASE(TestCaseName, TypeList);
//
// to declare it and specify the type parameters. As with TEST_F,
// TestCaseName must match the test fixture name.
// The list of types we want to test.
typedef Types<OnTheFlyPrimeTable, PreCalculatedPrimeTable> Implementations;
TYPED_TEST_CASE(PrimeTableTest, Implementations);
// Then use TYPED_TEST(TestCaseName, TestName) to define a typed test,
// similar to TEST_F.
TYPED_TEST(PrimeTableTest, ReturnsFalseForNonPrimes) {
// Inside the test body, you can refer to the type parameter by
// TypeParam, and refer to the fixture class by TestFixture. We
// don't need them in this example.
// Since we are in the template world, C++ requires explicitly
// writing 'this->' when referring to members of the fixture class.
// This is something you have to learn to live with.
EXPECT_FALSE(this->table_->IsPrime(-5));
EXPECT_FALSE(this->table_->IsPrime(0));
EXPECT_FALSE(this->table_->IsPrime(1));
EXPECT_FALSE(this->table_->IsPrime(4));
EXPECT_FALSE(this->table_->IsPrime(6));
EXPECT_FALSE(this->table_->IsPrime(100));
}
TYPED_TEST(PrimeTableTest, ReturnsTrueForPrimes) {
EXPECT_TRUE(this->table_->IsPrime(2));
EXPECT_TRUE(this->table_->IsPrime(3));
EXPECT_TRUE(this->table_->IsPrime(5));
EXPECT_TRUE(this->table_->IsPrime(7));
EXPECT_TRUE(this->table_->IsPrime(11));
EXPECT_TRUE(this->table_->IsPrime(131));
}
TYPED_TEST(PrimeTableTest, CanGetNextPrime) {
EXPECT_EQ(2, this->table_->GetNextPrime(0));
EXPECT_EQ(3, this->table_->GetNextPrime(2));
EXPECT_EQ(5, this->table_->GetNextPrime(3));
EXPECT_EQ(7, this->table_->GetNextPrime(5));
EXPECT_EQ(11, this->table_->GetNextPrime(7));
EXPECT_EQ(131, this->table_->GetNextPrime(128));
}
// That's it! Google Test will repeat each TYPED_TEST for each type
// in the type list specified in TYPED_TEST_CASE. Sit back and be
// happy that you don't have to define them multiple times.
#endif // GTEST_HAS_TYPED_TEST
#if GTEST_HAS_TYPED_TEST_P
using testing::Types;
// Sometimes, however, you don't yet know all the types that you want
// to test when you write the tests. For example, if you are the
// author of an interface and expect other people to implement it, you
// might want to write a set of tests to make sure each implementation
// conforms to some basic requirements, but you don't know what
// implementations will be written in the future.
//
// How can you write the tests without committing to the type
// parameters? That's what "type-parameterized tests" can do for you.
// It is a bit more involved than typed tests, but in return you get a
// test pattern that can be reused in many contexts, which is a big
// win. Here's how you do it:
// First, define a test fixture class template. Here we just reuse
// the PrimeTableTest fixture defined earlier:
template <class T>
class PrimeTableTest2 : public PrimeTableTest<T> {
};
// Then, declare the test case. The argument is the name of the test
// fixture, and also the name of the test case (as usual). The _P
// suffix is for "parameterized" or "pattern".
TYPED_TEST_CASE_P(PrimeTableTest2);
// Next, use TYPED_TEST_P(TestCaseName, TestName) to define a test,
// similar to what you do with TEST_F.
TYPED_TEST_P(PrimeTableTest2, ReturnsFalseForNonPrimes) {
EXPECT_FALSE(this->table_->IsPrime(-5));
EXPECT_FALSE(this->table_->IsPrime(0));
EXPECT_FALSE(this->table_->IsPrime(1));
EXPECT_FALSE(this->table_->IsPrime(4));
EXPECT_FALSE(this->table_->IsPrime(6));
EXPECT_FALSE(this->table_->IsPrime(100));
}
TYPED_TEST_P(PrimeTableTest2, ReturnsTrueForPrimes) {
EXPECT_TRUE(this->table_->IsPrime(2));
EXPECT_TRUE(this->table_->IsPrime(3));
EXPECT_TRUE(this->table_->IsPrime(5));
EXPECT_TRUE(this->table_->IsPrime(7));
EXPECT_TRUE(this->table_->IsPrime(11));
EXPECT_TRUE(this->table_->IsPrime(131));
}
TYPED_TEST_P(PrimeTableTest2, CanGetNextPrime) {
EXPECT_EQ(2, this->table_->GetNextPrime(0));
EXPECT_EQ(3, this->table_->GetNextPrime(2));
EXPECT_EQ(5, this->table_->GetNextPrime(3));
EXPECT_EQ(7, this->table_->GetNextPrime(5));
EXPECT_EQ(11, this->table_->GetNextPrime(7));
EXPECT_EQ(131, this->table_->GetNextPrime(128));
}
// Type-parameterized tests involve one extra step: you have to
// enumerate the tests you defined:
REGISTER_TYPED_TEST_CASE_P(
PrimeTableTest2, // The first argument is the test case name.
// The rest of the arguments are the test names.
ReturnsFalseForNonPrimes, ReturnsTrueForPrimes, CanGetNextPrime);
// At this point the test pattern is done. However, you don't have
// any real test yet as you haven't said which types you want to run
// the tests with.
// To turn the abstract test pattern into real tests, you instantiate
// it with a list of types. Usually the test pattern will be defined
// in a .h file, and anyone can #include and instantiate it. You can
// even instantiate it more than once in the same program. To tell
// different instances apart, you give each of them a name, which will
// become part of the test case name and can be used in test filters.
// The list of types we want to test. Note that it doesn't have to be
// defined at the time we write the TYPED_TEST_P()s.
typedef Types<OnTheFlyPrimeTable, PreCalculatedPrimeTable>
PrimeTableImplementations;
INSTANTIATE_TYPED_TEST_CASE_P(OnTheFlyAndPreCalculated, // Instance name
PrimeTableTest2, // Test case name
PrimeTableImplementations); // Type list
#endif // GTEST_HAS_TYPED_TEST_P
} // namespace