def base(graph):
''' Finds the base nodes of (un)directed graph. '''
base_nodes = {node for node in graph}
for node in graph:
if node in base_nodes:
for u, v in dfs(graph, node):
base_nodes.discard(v)
return base_nodes
def test_dfs_with_digraph_missing_node(self):
with self.assertRaises(NodeNotFound):
list(dfs(self.digraph, 'NotANode'))
def test_dfs_with_digraph(self):
self.assertEqual(list(dfs(self.digraph, 1)),
[(1, 2), (2, 3), (2, 4)])
def test_dfs_with_graph_missing_node(self):
with self.assertRaises(NodeNotFound):
list(dfs(self.graph, 999))
def test_dfs_with_graph(self):
self.assertEqual(list(dfs(self.graph, 1)),
[(1, 2), (2, 3), (2, 7), (7, 'Sofia'), (3, 5)])
