'If the path does not exist, file_contains does not match.'

def test_does_not_exist(self):

    path = self.make_temporary_path()
    arbitrary_matcher = Is(None)
    mismatch = file_contents(arbitrary_matcher).match(path)
    self.assertThat(mismatch.describe(), Equals(('%s    does    not    exist.' % path.path)))
