def test_contains_vertex(self):
"""Tests the contains_vertex method with a single vertex.
"""
data = { 'A' : [] }
graph = Graph(graph=data)
self.assertTrue(graph.contains_vertex('A'), 'The graph contains A.')
self.assertFalse(graph.contains_vertex('B'), 'The graph does not contain B.')
def test_add_vertex(self):
"""Tests the add_vertex method with an empty graph.
"""
graph = Graph()
self.assertFalse(graph.contains_vertex('A'), 'The graph does not contain A yet.')
graph.add_vertex('A')
self.assertTrue(graph.contains_vertex('A'), 'The graph now contains A.')
def test_remove_isolated_vertex(self):
"""Tests the remove_vertex method for an isolated vertex.
"""
data = { 'A' : [], 'B' : [] }
graph = Graph(graph=data)
self.assertTrue(graph.contains_vertex('A'), 'A is a vertex of the graph.')
self.assertTrue(graph.contains_vertex('B'), 'B is a vertex of the graph.')
graph.remove_vertex('A')
self.assertFalse(graph.contains_vertex('A'), 'The graph does not contain a vertex A.')
self.assertTrue(graph.contains_vertex('B'), 'The graph contains a vertex B.')
def test_add_vertex_existing_one(self):
"""Tests the add_vertex method in a graph where the vertex to add already exists.
"""
data = { 'A' : ['B'] }
graph = Graph(graph=data)
connected = graph.connected_vertex('A')
self.assertTrue(graph.contains_vertex('A'), 'Graph contains the vertex A.')
self.assertEqual(connected[0], 'B', 'A has an edge to vertex B.')
graph.add_vertex('A')
connected = graph.connected_vertex('A')
self.assertTrue(graph.contains_vertex('A'), 'Graph still contains vertex A.')
self.assertEqual(connected[0], 'B', 'A still has an edge to vertex B.')
