如何在具有多个测试.cpps的头文件中使用INSTANTIATE_TEST_CASE_P？

Question

假设我在头文件 Fixtures.h 中定义了一个 GTest 夹具：

 class baseFixture : public ::testing::Test{
   // some shared functionality among tests
 }

以及允许进行一些参数化的派生夹具：

class derivedFixture: public baseFixture, 
  public ::testing::WithParamInterface<std::tuple<bool, int>>{};

我想与 INSTANTIATE_TEST_CASE_P 一起使用，以便参数化分布在 N 个 .cpp 文件中的大量测试。我想在标题中写：

INSTANTIATE_TEST_CASE_P(derivedTests, derivedFixture, 
  ::testing::Combine(::testing::Bool(), ::testing::Values(1));

为了运行 {true, false} 和 {1} 的叉积的测试集。当我只编译一个 cpp 文件，将其命名为 N1.cpp，并运行可执行文件时，我的测试得到了正确的行为 -TEST_P(derivedFixture*它们每个运行两次。但是，当我构建整个项目并执行测试时，每个测试都会运行 2 * N 次。我在头文件中使用了包含保护来防止 INSTANTIATE 宏被调用两次，并且我确信我不会在其他地方调用它。

Answer 1

你所做的本质上是这样的：

夹具.hpp (1)

#ifndef FIXTURE_HPP
#define FIXTURE_HPP

#include <gtest/gtest.h>

struct fixture: ::testing::TestWithParam<std::tuple<bool, int>>
{};

INSTANTIATE_TEST_CASE_P(instantiation_one, fixture,
  ::testing::Combine(::testing::Bool(), ::testing::Values(1)));

#endif

t1.cpp

#include "fixture.hpp"
#include <tuple>

TEST_P(fixture, test_a)
{
    auto const & param = GetParam();
    std::cout << "param 0 = " << std::get<0>(param) << std::endl;
    std::cout << "param 1 = " << std::get<1>(param) << std::endl;
    SUCCEED();
}

t2.cpp

#include "fixture.hpp"
#include <tuple>

TEST_P(fixture, test_b)
{
    auto const & param = GetParam();
    std::cout << "param 0 = " << std::get<0>(param) << std::endl;
    std::cout << "param 1 = " << std::get<1>(param) << std::endl;
    SUCCEED();
}

主.cpp (1)

#include <gtest/gtest.h>

int main(int argc, char **argv) {
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}

编译、链接并运行：

$ ./gtester
[==========] Running 8 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 8 tests from instantiation_one/fixture
[ RUN      ] instantiation_one/fixture.test_a/0
param 0 = 0
param 1 = 1
[       OK ] instantiation_one/fixture.test_a/0 (0 ms)
[ RUN      ] instantiation_one/fixture.test_a/1
param 0 = 1
param 1 = 1
[       OK ] instantiation_one/fixture.test_a/1 (0 ms)
[ RUN      ] instantiation_one/fixture.test_a/0
param 0 = 0
param 1 = 1
[       OK ] instantiation_one/fixture.test_a/0 (0 ms)
[ RUN      ] instantiation_one/fixture.test_a/1
param 0 = 1
param 1 = 1
[       OK ] instantiation_one/fixture.test_a/1 (0 ms)
[ RUN      ] instantiation_one/fixture.test_b/0
param 0 = 0
param 1 = 1
[       OK ] instantiation_one/fixture.test_b/0 (0 ms)
[ RUN      ] instantiation_one/fixture.test_b/1
param 0 = 1
param 1 = 1
[       OK ] instantiation_one/fixture.test_b/1 (0 ms)
[ RUN      ] instantiation_one/fixture.test_b/0
param 0 = 0
param 1 = 1
[       OK ] instantiation_one/fixture.test_b/0 (0 ms)
[ RUN      ] instantiation_one/fixture.test_b/1
param 0 = 1
param 1 = 1
[       OK ] instantiation_one/fixture.test_b/1 (0 ms)
[----------] 8 tests from instantiation_one/fixture (0 ms total)

[----------] Global test environment tear-down
[==========] 8 tests from 1 test case ran. (1 ms total)
[  PASSED  ] 8 tests.

当您预期有 4 个测试时，您会看到 8 个测试，每个测试在 {0,1} 中instantiation_one/fixture.test_a/N运行两次N。

错误是这样的：我们这样做：

INSTANTIATE_TEST_CASE_P(instantiation_one, fixture,
  ::testing::Combine(::testing::Bool(), ::testing::Values(1)));

in fixture.hpp，它是#include-ed 的，因此在每个翻译单元 tN.cpp中重复，导致由该代码注册的 2 个参数化测试在运行时注册N多次，因此运行 N 次。

我们应该只为给定的一组值编译一次值参数化夹具的每个实例，因此仅在一个源文件中执行此操作，例如

夹具.hpp (2)

#ifndef FIXTURE_HPP
#define FIXTURE_HPP

#include <gtest/gtest.h>

struct fixture: ::testing::TestWithParam<std::tuple<bool, int>>
{};


#endif

主.cpp (2)

#include <gtest/gtest.h>
#include "fixture.hpp"

INSTANTIATE_TEST_CASE_P(instantiation_one, fixture,
  ::testing::Combine(::testing::Bool(), ::testing::Values(1)));

int main(int argc, char **argv) {
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}

重新编译、重新链接并重新运行：

$ g++ -Wall -Wextra -c main.cpp t1.cpp t2.cpp
$ g++ -o gtester main.o t1.o t2.o -lgtest -pthread
$ ./gtester
[==========] Running 4 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 4 tests from instantiation_one/fixture
[ RUN      ] instantiation_one/fixture.test_a/0
param 0 = 0
param 1 = 1
[       OK ] instantiation_one/fixture.test_a/0 (0 ms)
[ RUN      ] instantiation_one/fixture.test_a/1
param 0 = 1
param 1 = 1
[       OK ] instantiation_one/fixture.test_a/1 (0 ms)
[ RUN      ] instantiation_one/fixture.test_b/0
param 0 = 0
param 1 = 1
[       OK ] instantiation_one/fixture.test_b/0 (1 ms)
[ RUN      ] instantiation_one/fixture.test_b/1
param 0 = 1
param 1 = 1
[       OK ] instantiation_one/fixture.test_b/1 (0 ms)
[----------] 4 tests from instantiation_one/fixture (1 ms total)

[----------] Global test environment tear-down
[==========] 4 tests from 1 test case ran. (1 ms total)
[  PASSED  ] 4 tests.