def test_undirected_graph_is_connected(self):
""" Get whether a path exists for every pair of vertices in an
undirected graph """
g_connected = UndirectedGraph.from_dict({'v0': [('v1',), ('v2',)],
'v1': [],
'v2': []})
g_disconnected = UndirectedGraph.from_dict({'v0': [('v1',)],
'v1': [],
'v2': []})
self.assertTrue(g_connected.is_connected)
self.assertFalse(g_disconnected.is_connected)
with self.assertRaises(AttributeError):
g_connected.is_connected = False
with self.assertRaises(AttributeError):
g_disconnected.is_connected = True
def test_bad_undirected_graph_input(self):
""" An undirected graph from_dict input must be of a certain form """
graph_dict = {'v0': ['v1', {'weight': 3}],
'v1': [],
'v2': []}
with self.assertRaises(ValueError):
_ = UndirectedGraph.from_dict(graph_dict)
def test_undirected_graph_num_vertices_and_num_edges(self):
""" Get the number of an undirected graph's vertices and edges """
g = UndirectedGraph.from_dict({'v0': [('v1',)],
'v1': []})
self.assertEqual(g.num_vertices, 2)
self.assertEqual(g.num_edges, 1)
with self.assertRaises(AttributeError):
g.num_vertices = 0
with self.assertRaises(AttributeError):
g.num_edges = 0
def test_undirected_graph_average_degree(self):
""" Get the average degree of all vertices in an undirected graph """
g = UndirectedGraph.from_dict({'v0': [('v1',)],
'v1': [],
'v2': []})
empty_g = UndirectedGraph()
self.assertEqual(g.average_degree, 2.0 / 3.0)
with self.assertRaises(AttributeError):
g.average_degree = 0
self.assertEqual(empty_g.average_degree, 0)
def test_create_undirected_graph_from_dict(self):
""" Create an undirected graph from an adjacency dictionary """
graph_dict = {'v0': [(1,), (1,), ((2, 2), {'weight': 5})],
1: [('v0',), ('v3',)],
(2, 2): [],
'v3': [],
'v4': []}
vertex_attrs = {'v0': {'city': 'Paris'},
1: {'continent': 'Europe', 'city': 'London'},
'v5': {'city': 'Jamestown'}}
g = UndirectedGraph.from_dict(graph_dict, vertex_attrs=vertex_attrs)
v0 = g.get_vertex('v0')
v1 = g.get_vertex(1)
v2 = g.get_vertex((2, 2))
v3 = g.get_vertex('v3')
v4 = g.get_vertex('v4')
v5 = g.get_vertex('v5')
e01 = g.get_edge(('v0', 1))
e02 = g.get_edge(('v0', (2, 2)))
e13 = g.get_edge((1, 'v3'))
self.assertEqual(g.num_vertices, 6)
self.assertEqual(g.num_edges, 3)
self.assertEqual(set(v0.neighbors), set([v1, v2]))
self.assertEqual(set(v1.neighbors), set([v0, v3]))
self.assertEqual(set(v2.neighbors), set([v0]))
self.assertEqual(set(v3.neighbors), set([v1]))
self.assertEqual(set(v4.neighbors), set())
self.assertEqual(set(v5.neighbors), set())
self.assertEqual(v0.get('city'), 'Paris')
self.assertEqual(v1.get('continent'), 'Europe')
self.assertEqual(v1.get('city'), 'London')
self.assertEqual(v5.get('city'), 'Jamestown')
self.assertIsNone(v2.get('city'))
self.assertIsNone(e01.get('weight'))
self.assertEqual(e02.get('weight'), 5)
self.assertIsNone(e13.get('weight'))
with self.assertRaises(ValueError):
_ = UndirectedGraph.from_dict({'v0': [({'weight': 5},)],
'v1': [({'weight': 3},)]})
