googletest/samples/sample7_unittest.cc

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// Author: vladl@google.com (Vlad Losev)

// This sample shows how to test common properties of multiple
// implementations of an interface (aka interface tests) using
// value-parameterized tests. Each test in the test case has
// a parameter that is an interface pointer to an implementation
// tested.

// The interface and its implementations are in this header.
#include "prime_tables.h"

#include "gtest/gtest.h"

#if GTEST_HAS_PARAM_TEST

using ::testing::TestWithParam;
using ::testing::Values;

// As a general rule, to prevent a test from affecting the tests that come
// after it, you should create and destroy the tested objects for each test
// instead of reusing them.  In this sample we will define a simple factory
// function for PrimeTable objects.  We will instantiate objects in test's
// SetUp() method and delete them in TearDown() method.
typedef PrimeTable* CreatePrimeTableFunc();

PrimeTable* CreateOnTheFlyPrimeTable() {
  return new OnTheFlyPrimeTable();
}

template <size_t max_precalculated>
PrimeTable* CreatePreCalculatedPrimeTable() {
  return new PreCalculatedPrimeTable(max_precalculated);
}

// Inside the test body, fixture constructor, SetUp(), and TearDown() you
// can refer to the test parameter by GetParam().  In this case, the test
// parameter is a factory function which we call in fixture's SetUp() to
// create and store an instance of PrimeTable.
class PrimeTableTest : public TestWithParam<CreatePrimeTableFunc*> {
 public:
  virtual ~PrimeTableTest() { delete table_; }
  virtual void SetUp() { table_ = (*GetParam())(); }
  virtual void TearDown() {
    delete table_;
    table_ = NULL;
  }

 protected:
  PrimeTable* table_;
};

TEST_P(PrimeTableTest, ReturnsFalseForNonPrimes) {
  EXPECT_FALSE(table_->IsPrime(-5));
  EXPECT_FALSE(table_->IsPrime(0));
  EXPECT_FALSE(table_->IsPrime(1));
  EXPECT_FALSE(table_->IsPrime(4));
  EXPECT_FALSE(table_->IsPrime(6));
  EXPECT_FALSE(table_->IsPrime(100));
}

TEST_P(PrimeTableTest, ReturnsTrueForPrimes) {
  EXPECT_TRUE(table_->IsPrime(2));
  EXPECT_TRUE(table_->IsPrime(3));
  EXPECT_TRUE(table_->IsPrime(5));
  EXPECT_TRUE(table_->IsPrime(7));
  EXPECT_TRUE(table_->IsPrime(11));
  EXPECT_TRUE(table_->IsPrime(131));
}

TEST_P(PrimeTableTest, CanGetNextPrime) {
  EXPECT_EQ(2, table_->GetNextPrime(0));
  EXPECT_EQ(3, table_->GetNextPrime(2));
  EXPECT_EQ(5, table_->GetNextPrime(3));
  EXPECT_EQ(7, table_->GetNextPrime(5));
  EXPECT_EQ(11, table_->GetNextPrime(7));
  EXPECT_EQ(131, table_->GetNextPrime(128));
}

// In order to run value-parameterized tests, you need to instantiate them,
// or bind them to a list of values which will be used as test parameters.
// You can instantiate them in a different translation module, or even
// instantiate them several times.
//
// Here, we instantiate our tests with a list of two PrimeTable object
// factory functions:
INSTANTIATE_TEST_CASE_P(
    OnTheFlyAndPreCalculated,
    PrimeTableTest,
    Values(&CreateOnTheFlyPrimeTable, &CreatePreCalculatedPrimeTable<1000>));

#else

// Google Test may not support value-parameterized tests with some
// compilers. If we use conditional compilation to compile out all
// code referring to the gtest_main library, MSVC linker will not link
// that library at all and consequently complain about missing entry
// point defined in that library (fatal error LNK1561: entry point
// must be defined). This dummy test keeps gtest_main linked in.
TEST(DummyTest, ValueParameterizedTestsAreNotSupportedOnThisPlatform) {}

#endif  // GTEST_HAS_PARAM_TEST