def test_conditional(self):
"""Test with conditions."""
s = "helloworld"
r = 5
allowed_prefixes = {"o", "ol", "old", "oldh", "oldhl", "oldhlr"}
all_perms = set("".join(p) for p in permutations(s, r))
cond_perms = set(conditional_perms(s, r,
lambda x: x in allowed_prefixes))
for p in all_perms:
if p in cond_perms:
self.assertTrue(p[:-1] in allowed_prefixes)
else:
self.assertFalse(any(p[:-1] == pre
for pre in allowed_prefixes))
def test_0_len_perms(self):
"""Test that there should be only 1 0-length permutation."""
self.assertListEqual(list(conditional_perms("helloworld", 0)), [""])
def _test_unconditional(self, s, r):
perms1 = set("".join(p) for p in permutations(s, r))
perms2 = set(conditional_perms(s, r))
self.assertSetEqual(perms1, perms2)
