'If the input data does not end with a separator, then every line ends
with a separator *except* the last line.'

@given(lists(binary(min_size=1), min_size=1), binary(min_size=1))
def test_nonterminated_line(self, data, separator):

    assume((not ''.join(data).endswith(separator)))
    observed = list(_iter_lines(iter(data), separator))
    self.expectThat(observed[:(-1)], AllMatch(EndsWith(separator)))
    self.assertThat(observed[(-1)], Not(EndsWith(separator)))
