def METHOD_NAME(self):
    result = self.run_command(["help", "nil", "--base", "core20"])
    expected = "Displaying help for the 'nil' plugin for 'core20'."
    output = result.output[: len(expected)]
    self.expectThat(
        output,
        Equals(expected),
        "The help message does not start with {!r} but with "
        "{!r} instead".format(expected, output),
    )