def test_cycle_that_doesnt_involve_start(self):
self.assertIsNone(
validation.find_cycle('A', {
'A': ['B'],
'B': ['C'],
'C': ['B'],
}))
def test_longer_cycle(self):
self.assertEqual(
validation.find_cycle('A', {
'A': ['B'],
'B': ['C'],
'C': ['A'],
}), ['A', 'B', 'C', 'A'])
def test_no_cycles(self):
self.assertIsNone(
validation.find_cycle('A', {
'A': ['B', 'C'],
'B': ['C'],
'C': [],
}))
def test_diamon_with_cycle(self):
self.assertEqual(
validation.find_cycle('A', {
'A': ['B1', 'B2'],
'B1': ['C'],
'B2': ['C'],
'C': ['A'],
}), ['A', 'B1', 'C', 'A'])
def test_many_cycles_but_only_one_has_start(self):
self.assertEqual(
validation.find_cycle('A', {
'A': ['B'],
'B': ['C'],
'C': ['B', 'D'],
'D': ['B', 'C', 'A'],
}), ['A', 'B', 'C', 'D', 'A'])
def test_trivial_cycle(self):
self.assertEqual(validation.find_cycle('A', {
'A': ['A'],
}), ['A', 'A'])