GoogleTest: is there a generic way to add a function call prior to each test case? - googletest

Question

my scenario: I have an existing unit test framework with ~3000 individual test cases. They are made from TEST, TEST_F and TEST_P macros.
Internally the tested modules make use of a logger library and now my goal is to create individual log files for each test case. To do so I would like to call a function as a SetUp for each test case.
Is there a way to register such function at the framework and get it called automatically?
The obvious solution for me would look like: do the work in a test fixture constructor or SetUp() but then I'd have to touch every single test case.
I do like the idea of registering a global setup at the framework with AddGlobalTestEnvironment() but as I understand this is handled only once per executable.
By the way: I have acceptance tests implemented in robot test and guess what? I want to repeat the task there...
Thanks for any inspiration!
Christoph

Answer 1

You mentioned:
The obvious solution for me would look like: do the work in a test fixture constructor or SetUp() but then I'd have to touch every single test case.
If the reason that you think you would need to touch every single test case is to set the filename differently, you can use the combination of SetUp() function and the current_test_info provided by GTest to get the test name for each test, and then use that to create a separate file for each test.
Here is an example:
// Class for test fixture
class MyTestFixture : public ::testing::Test {
protected:
void SetUp() override {
test_name_ = std::string(
::testing::UnitTest::GetInstance()->current_test_info()->name());
std::cout << "test_name_: " << test_name_ << std::endl;
// CreateYourLogFileUsingTestName(test_name_);
}
std::string test_name_;
};
TEST_F(MyTestFixture, Test1) {
EXPECT_EQ(this->test_name_, std::string("Test1"));
}
TEST_F(MyTestFixture, Test2) {
EXPECT_EQ(this->test_name_, std::string("Test2"));
}
Live example here: https://godbolt.org/z/YjzEG3G77

Answer 2

The solution I found in the gtest docs:
class TraceHandler : public testing::EmptyTestEventListener
{
// Called before a test starts.
void OnTestStart( const testing::TestInfo& test_info ) override
{
// set the logfilename here
}
// Called after a test ends.
void OnTestEnd( const testing::TestInfo& test_info ) override
{
// close the log here
}
};
int main( int argc, char** argv )
{
testing::InitGoogleTest( &argc, argv );
testing::TestEventListeners& listeners =
testing::UnitTest::GetInstance()->listeners();
// Adds a listener to the end. googletest takes the ownership.
listeners.Append(new TraceHandler);
return RUN_ALL_TESTS();
}
This way it automatically applies to all tests linked to this main-function.
Maybe I have to mention: my logger is a collection of static functions that send udp-packets to a receiver that cares for actual logging. I can control the filename by one of that functions. That's the reason why I don't need to insert code in every single TEST, TEST_F or TEST_P.