使用INSTANTIATE_TEST_CASE_P针对同一灯具的不同实例

Question

我们可以使用INSTANTIATE_TEST_CASE_P对同一测试夹具有两个不同的实例吗

Answer 1

Certainly. Here is an elementary example:

gtester.cpp

#include <gtest/gtest.h>
#include <string>

class my_fixture :
    public ::testing::TestWithParam<std::string> {
};


INSTANTIATE_TEST_CASE_P(Colours,my_fixture,
    ::testing::Values("red", "green", "blue"));

INSTANTIATE_TEST_CASE_P(Shapes,my_fixture,
    ::testing::Values("square", "circle", "triangle"));


TEST_P(my_fixture, has_positive_size) {
    auto const & val = GetParam();
  ASSERT_TRUE(val.size() > 0);
}

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

Compile:

$ g++ -std=c++11 -Wall -Wextra -c gtester.cpp

Link:

$ g++ -o gtester gtester.o -lgtest -pthread

Run:

$ ./gtester
[==========] Running 6 tests from 2 test cases.
[----------] Global test environment set-up.
[----------] 3 tests from Colours/my_fixture
[ RUN      ] Colours/my_fixture.has_positive_size/0
[       OK ] Colours/my_fixture.has_positive_size/0 (0 ms)
[ RUN      ] Colours/my_fixture.has_positive_size/1
[       OK ] Colours/my_fixture.has_positive_size/1 (0 ms)
[ RUN      ] Colours/my_fixture.has_positive_size/2
[       OK ] Colours/my_fixture.has_positive_size/2 (0 ms)
[----------] 3 tests from Colours/my_fixture (0 ms total)

[----------] 3 tests from Shapes/my_fixture
[ RUN      ] Shapes/my_fixture.has_positive_size/0
[       OK ] Shapes/my_fixture.has_positive_size/0 (0 ms)
[ RUN      ] Shapes/my_fixture.has_positive_size/1
[       OK ] Shapes/my_fixture.has_positive_size/1 (0 ms)
[ RUN      ] Shapes/my_fixture.has_positive_size/2
[       OK ] Shapes/my_fixture.has_positive_size/2 (0 ms)
[----------] 3 tests from Shapes/my_fixture (0 ms total)

[----------] Global test environment tear-down
[==========] 6 tests from 2 test cases ran. (0 ms total)
[  PASSED  ] 6 tests.

Run the Colours tests only:

$ ./gtester --gtest_filter=Colours/* 
Note: Google Test filter = Colours/*
[==========] Running 3 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 3 tests from Colours/my_fixture
[ RUN      ] Colours/my_fixture.has_positive_size/0
[       OK ] Colours/my_fixture.has_positive_size/0 (0 ms)
[ RUN      ] Colours/my_fixture.has_positive_size/1
[       OK ] Colours/my_fixture.has_positive_size/1 (0 ms)
[ RUN      ] Colours/my_fixture.has_positive_size/2
[       OK ] Colours/my_fixture.has_positive_size/2 (0 ms)
[----------] 3 tests from Colours/my_fixture (0 ms total)

[----------] Global test environment tear-down
[==========] 3 tests from 1 test case ran. (1 ms total)
[  PASSED  ] 3 tests.

Run the Shapes tests only:

$ ./gtester --gtest_filter=Shapes/* 
Note: Google Test filter = Shapes/*
[==========] Running 3 tests from 1 test case.
[----------] Global test environment set-up.
[----------] 3 tests from Shapes/my_fixture
[ RUN      ] Shapes/my_fixture.has_positive_size/0
[       OK ] Shapes/my_fixture.has_positive_size/0 (0 ms)
[ RUN      ] Shapes/my_fixture.has_positive_size/1
[       OK ] Shapes/my_fixture.has_positive_size/1 (0 ms)
[ RUN      ] Shapes/my_fixture.has_positive_size/2
[       OK ] Shapes/my_fixture.has_positive_size/2 (0 ms)
[----------] 3 tests from Shapes/my_fixture (0 ms total)

[----------] Global test environment tear-down
[==========] 3 tests from 1 test case ran. (0 ms total)
[  PASSED  ] 3 tests.

In a more likelife scenario:-

my_fixture is developed by programmer Alice, and implemented in a header file my_fixture.h and (if necessary) a library lib_myfixture .

The Colours tests are developed by programmer Bob, in a separate test-suite implemented in:-

colour_test.cpp

#include <my_fixture.h>

INSTANTIATE_TEST_CASE_P(Colours,my_fixture,
    ::testing::Values("red", "green", "blue"));

TEST_P(my_fixture, ...) {
    ...
}

...

which is built like:

$ g++ -std=c++11 -Wall -Wextra -I/my_fixture/include/path -c colour_test.cpp
$ g++ -o colour_test colour_test.o -L/my_fixture/lib/path -lmy_fixture -lgtest -pthread

And the Shapes tests are developed by programmer Carol, in another separate test-suite, implemented in the same way.

Later

What I wanted to know is if it is possible to couple an instantiation with specific TEST_Ps... and another one coupled with another set of TEST_Ps for the same test fixture.

No, you can't do that, because a TEST_P(fixture,description) is bound to fixture , not to an instantiation of fixture . But given any fixture it is trivial to make two functionally identical fixtures that are instantiated differently, eg

#include <gtest/gtest.h>
#include <string>

class my_fixture :
    public ::testing::TestWithParam<std::string> {
};

class colours_fixture : public my_fixture {};
class shapes_fixture : public my_fixture {};


INSTANTIATE_TEST_CASE_P(Colours,colours_fixture,
    ::testing::Values("red", "green", "blue"));

INSTANTIATE_TEST_CASE_P(Shapes,shapes_fixture,
    ::testing::Values("square", "circle", "triangle"));


TEST_P(colours_fixture, has_positive_size) {
    auto const & val = GetParam();
  ASSERT_TRUE(val.size() > 0);
}

TEST_P(shapes_fixture, has_positive_size) {
    auto const & val = GetParam();
  ASSERT_TRUE(val.size() > 0);
}

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