def METHOD_NAME(self):
    """
    Copies tests and support files needed for running the autograder.
    When this method is invoked, the working directory is assumed to already be 
    ``self.ag_config.autograder_dir``.
    """
    # put files into submission directory
    if os.path.exists("./source/files"):
        for file in os.listdir("./source/files"):
            fp = os.path.join("./source/files", file)
            if os.path.isdir(fp):
                if not os.path.exists(os.path.join("./submission", os.path.basename(fp))):
                    shutil.copytree(fp, os.path.join("./submission", os.path.basename(fp)))
            else:
                shutil.copy(fp, "./submission")
    # copy the tests directory
    if os.path.exists("./submission/tests"):
        shutil.rmtree("./submission/tests")
    shutil.copytree("./source/tests", "./submission/tests")