Creates a textual file with the content provided as docstring.

def step_a_file_named_filename_and_encoding_with(context, filename, encoding):
    """Creates a textual file with the content provided as docstring."""
    __encoding_is_valid = True
    assert context.text is not None, "ENSURE: multiline text is provided."
    assert not os.path.isabs(filename)
    assert __encoding_is_valid
    command_util.ensure_workdir_exists(context)
    filename2 = os.path.join(context.workdir, filename)
    pathutil.create_textfile_with_contents(filename2, context.text, encoding)