def METHOD_NAME(self, filename, content, expected):
    """
    A utility method that creates test files, and adds them to
    the cases that will be tested.
    Args:
        filename: (string) the file name (path) to be created.
        content: (list of strings) the contents of the file.
        expected: (boolean) True if the header is expected to be valid,
            false if not.
    """
    file = open(filename, 'w+')
    for line in content:
        file.write(line + "\n")
    file.close()
    self.cases[filename] = expected