C++ modules: tests partition setup works on linux but not on windows.

[mrwsl]

I want to switch to modules and was thinking about a layout for tests. It is important for me to test also not exported methods. My idea was to create a tests partition that is only loaded if a specific expression ENABLE_TESTS is set:

export module Module;

export import :common;

#ifdef ENABLE_TESTS
export import :tests;
#endif

ENABLE_TESTS is set by CMake. I then have a simple tests-main that imports the Module:

#include "gtest/gtest.h"

import Module;

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

This set-up works on Linux but not on Windows. On Windows the binary is built but running it shows zero tests. I have no clue why this is happening and if it is a CMake, Windows or gtest problem.

Is anyone utlizing gtest in combination with modules? If yes, how?

I attached a minimal example.

modulestest.zip

[mrwsl]

Five minutes later - the solution: setting the target sources for the tests target directly works.

  target_sources(tests
    PUBLIC
      FILE_SET cxx_modules TYPE CXX_MODULES
      BASE_DIRS ${CMAKE_SOURCE_DIR}/tests
      FILES Module.tests.ixx
  )

No idea why this is necessary though.