def test_updateAndDeleteEdge(self):
G = Graph()
# add an edge
G.addTown('1')
G.addTown('2')
G.addOrUpdateEdge('1', '2', 3)
assert str(G) == 'Town: 1\n ->2 3\nTown: 2\n'
# add another edge
G.addTown('3')
G.addOrUpdateEdge('1', '3', 4)
self.assertRegexpMatches(str(G), r'->2 3')
self.assertRegexpMatches(str(G), r'->3 4')
# update the first edge
G.addOrUpdateEdge('1', '2', 4)
self.assertRegexpMatches(str(G), r'->2 4')
# add an illegal edge
with self.assertRaises(Exception) as context:
G.addOrUpdateEdge('4', '3', 2)
self.assertEqual(context.exception.message, 'Origin does not exist.')
# delete the first edge
G.deleteEdge('1', '2')
self.assertNotRegexpMatches(str(G), r'->2 4')
# delete the Town 1 which is part of the only remaining edge
G.deleteTown('1')
self.assertNotRegexpMatches(str(G), r'->3 4')
def test_addAndDeleteTown(self):
G = Graph()
# delete a town from an empty graph
with self.assertRaises(Exception) as context:
G.deleteTown('1')
self.assertEqual(context.exception.message, 'Town does not exist.')
# add a town
G.addTown('1')
assert str(G) == 'Town: 1\n'
# add another town
G.addTown('2')
assert str(G) == 'Town: 1\nTown: 2\n'
# delete a town that has just been added
G.deleteTown('2')
assert str(G) == 'Town: 1\n'
# delete a town which doesn't exist
with self.assertRaises(Exception) as context:
G.deleteTown('3')
self.assertEqual(context.exception.message, 'Town does not exist.')
# delete the last remaining town
G.deleteTown('1')
assert str(G) == ''
