The type used for functions that operate on test fixtures. This is used for the fixture setup and teardown functions as well as for the testcases themselves.

user_data is a pointer to the data that was given when registering the test case.

fixture will be a pointer to the area of memory allocated by the test framework, of the size requested. If the requested size was zero then fixture will be equal to user_data.

alias GTestFixtureFunc = void function(void* fixture, void* userData)