What does enable_testing() do in cmake?

Question

I see that to add my google tests(for my cpp project), I need to make a call to enable_testing() in the root source directory. Can someone explain what this really does? Also why would cmake not make this default?

This is all I could get from the documentation.

Enables testing for this directory and below. See also the add_test() command. Note that ctest expects to find a test file in the build directory root. Therefore, this command should be in the source directory root.

Answer 1

When you call add_test(...), CMake will not generate the tests unless enable_testing() has been called. Note that you usually don't need to call this directly. Just include(CTest) and it will invoke it for you.

My CMake setup often looks like this:

include(CTest) # note: this adds a BUILD_TESTING which defaults to ON  # ...  if(BUILD_TESTING)   add_subdirectory(tests) endif() 

In the tests directory:

# setup test dependencies # googletest has some code they explain on how to set it up; put that here  add_executable(MyUnitTests     # ... )  target_link_libraries(MyUnitTests gtest_main)  add_test(MyUnitTestName MyUnitTests)