When the build step of type Tests runs it will fail if there are no tests to run. This is not always desirable and there should be a way to disregard this step if no tests are present. Most build tools compile test source into a standard directory and if that is empty it could meet this criteria. Other languages that are not compiled may call for a creative solution or just some mechanism versatile enough for a general case like some combination of file search and grep of files for a 'test flag'.