def test_add_edge(self):
graph = BidirectionalGraph()
source = BDNode('source')
dest = BDNode('dest')
fake_source = 'source'
fake_dest = 'dest'
# Trying to add an edge with non-nodes returns None
self.assertIsNone(graph.add_edge(source, fake_dest))
self.assertIsNone(graph.add_edge(fake_source, dest))
self.assertIsNone(graph.add_edge(fake_source, fake_dest))
# Trying to add an edge when both nodes aren't in the graph returns None
self.assertIsNone(graph.add_edge(source, dest))
graph.add_node(source)
self.assertIsNone(graph.add_edge(source, dest))
graph.add_node(dest)
# Adding an edge with both nodes in the graph returns a new edge,
# if the edge doesn't yet exist in the graph
res = graph.add_edge(source, dest)
self.assertIsInstance(res, BDEdge)
self.assertEqual(res.count, 1)
# Adding an edge with both nodes in the graph increments the count of
# the edge that already exists
inc = graph.add_edge(source, dest)
self.assertIsInstance(inc, BDEdge)
self.assertEqual(inc, res)
self.assertEqual(inc.count, 2)
def test_add_edge(self):
graph = BidirectionalGraph()
source = BDNode("source")
dest = BDNode("dest")
fake_source = "source"
fake_dest = "dest"
# Trying to add an edge with non-nodes returns None
self.assertIsNone(graph.add_edge(source, fake_dest))
self.assertIsNone(graph.add_edge(fake_source, dest))
self.assertIsNone(graph.add_edge(fake_source, fake_dest))
# Trying to add an edge when both nodes aren't in the graph returns None
self.assertIsNone(graph.add_edge(source, dest))
graph.add_node(source)
self.assertIsNone(graph.add_edge(source, dest))
graph.add_node(dest)
# Adding an edge with both nodes in the graph returns a new edge,
# if the edge doesn't yet exist in the graph
res = graph.add_edge(source, dest)
self.assertIsInstance(res, BDEdge)
self.assertEqual(res.count, 1)
# Adding an edge with both nodes in the graph increments the count of
# the edge that already exists
inc = graph.add_edge(source, dest)
self.assertIsInstance(inc, BDEdge)
self.assertEqual(inc, res)
self.assertEqual(inc.count, 2)
