def test_compare(self, size):
        s1 = '-' * size
        s2 = '-' * size
        self.failUnless(s1 == s2)
        del s2
        s2 = s1 + 'a'
        self.failIf(s1 == s2)
        del s2
        s2 = '.' * size
        self.failIf(s1 == s2)