diff options
Diffstat (limited to 'Lib/test/test_itertools.py')
| -rw-r--r-- | Lib/test/test_itertools.py | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py index 63ca17b6e4..ba726b5431 100644 --- a/Lib/test/test_itertools.py +++ b/Lib/test/test_itertools.py @@ -44,6 +44,10 @@ def take(n, seq): 'Convenience function for partially consuming a long of infinite iterable' return list(islice(seq, n)) +def fact(n): + 'Factorial' + return reduce(operator.mul, range(1, n+1), 1) + class TestBasicOps(unittest.TestCase): def test_chain(self): self.assertEqual(list(chain('abc', 'def')), list('abcdef')) @@ -52,6 +56,26 @@ class TestBasicOps(unittest.TestCase): self.assertEqual(take(4, chain('abc', 'def')), list('abcd')) self.assertRaises(TypeError, chain, 2, 3) + def test_combinations(self): + self.assertRaises(TypeError, combinations, 'abc') # missing r argument + self.assertRaises(TypeError, combinations, 'abc', 2, 1) # too many arguments + self.assertRaises(ValueError, combinations, 'abc', -2) # r is negative + self.assertRaises(ValueError, combinations, 'abc', 32) # r is too big + self.assertEqual(list(combinations(range(4), 3)), + [(0,1,2), (0,1,3), (0,2,3), (1,2,3)]) + for n in range(8): + values = [5*x-12 for x in range(n)] + for r in range(n+1): + result = list(combinations(values, r)) + self.assertEqual(len(result), fact(n) / fact(r) / fact(n-r)) # right number of combs + self.assertEqual(len(result), len(set(result))) # no repeats + self.assertEqual(result, sorted(result)) # lexicographic order + for c in result: + self.assertEqual(len(c), r) # r-length combinations + self.assertEqual(len(set(c)), r) # no duplicate elements + self.assertEqual(list(c), sorted(c)) # keep original ordering + self.assert_(all(e in values for e in c)) # elements taken from input iterable + def test_count(self): self.assertEqual(lzip('abc',count()), [('a', 0), ('b', 1), ('c', 2)]) self.assertEqual(lzip('abc',count(3)), [('a', 3), ('b', 4), ('c', 5)]) |