def test_graph_cycle_detection(self):
nodes = [
Node('A'),
Node('B'),
Node('C'),
Node('D'),
Node('E'),
Node('F')
]
simple_edges = [Edge(a, b) for a, b in pairwise(nodes)]
graph = Graph()
for edge in simple_edges:
graph.add_edge(edge)
self.assertTrue(graph.is_cyclefree)
self.assertFalse(graph.edge_cycles)
self.assertFalse(graph.node_cycles)
# add one cycle
graph.add_edge(Edge(nodes[1], nodes[0]))
self.assertFalse(graph.is_cyclefree)
self.assertEqual(len(graph.node_cycles), 1)
# add second cycle
graph.add_edge(Edge(nodes[2], nodes[0]))
self.assertEqual(len(graph.node_cycles), 2)
# add third cycle
graph.add_edge(Edge(nodes[5], nodes[4]))
self.assertEqual(len(graph.node_cycles), 3)
# add tricky edge (adds multiple cycles at once)
graph.add_edge(Edge(nodes[4], nodes[2]))
self.assertGreater(len(graph.node_cycles), 4)
self.assertGreater(len(graph.edge_cycles), 4)
def test_raise_cycle_exceptions(self):
nodes = [
Node('A'),
Node('B'),
Node('C'),
Node('D'),
Node('E'),
Node('F')
]
simple_edges = [Edge(a, b) for a, b in pairwise(nodes)]
graph = Graph()
for edge in simple_edges:
graph.add_edge(edge)
# should not raise CycleExceptions
graph.get_nodepaths()
graph.get_edgepaths()
# add one cycle
graph.add_edge(Edge(nodes[1], nodes[0]))
# should raise suitable exceptions
self.assertRaises(CycleNodeException, lambda: graph.get_nodepaths())
self.assertRaises(CycleEdgeException, lambda: graph.get_edgepaths())
# CycleNodeException message should contain
# cycling nodes (order is undetermined)
try:
graph.get_nodepaths()
except CycleNodeException as e:
self.assertIn(e.args[0], [[nodes[0], nodes[1], nodes[0]],
[nodes[1], nodes[0], nodes[1]]])
def test_edge(self):
n1 = Node('A')
n2 = Node('B')
edge1 = Edge(n1, n2)
edge2 = Edge(n1, n2)
edge3 = Edge(n2, n1)
self.assertIs(edge1, edge2)
self.assertTrue(edge1 == edge2)
self.assertTrue(edge1 != edge3)
self.assertEqual(str(edge1), 'Edge A-B')
self.assertEqual(str(edge1), repr(edge1))
def test_transitive_reduction(self):
self.ga.transitive_reduction()
# before '##' has edge to all cfs: c1, c2, c3, c4
# after '##' has only one edge to c1
self.assertEqual(
[edge for edge in self.ga.edges if edge.left == Node('##')],
[Edge(Node('##'), Node('c1'))])
def test_graph_autoadd_nodes(self):
n1 = Node('A')
n2 = Node('B')
edge = Edge(n1, n2)
graph = Graph()
graph.add_edge(edge)
self.assertIn(edge, graph.edges)
self.assertIn(n1, graph.nodes)
self.assertIn(n2, graph.nodes)
def test_contains_all_needed_edges(self):
# depsX {key: [valueX]} contains all edges as Edge(valueX, key) ...
# + '##' edge to all cfs
edges = []
for key, sources in self.depsA.items():
right = Node(key)
for src in sources:
edges.append(Edge(Node(src), right))
edges.append(Edge(Node('##'), right))
self.assertEqual(set(edges), self.ga.edges)
edges = []
for key, sources in self.depsB.items():
right = Node(key)
for src in sources:
edges.append(Edge(Node(src), right))
edges.append(Edge(Node('##'), right))
self.assertEqual(set(edges), self.gb.edges)
def test_paths(self):
nodes = [Node('A'), Node('B'), Node('C'), Node('D'), Node('E'), Node('F')]
simple_edges = [Edge(a, b) for a, b in pairwise(nodes)]
graph = Graph()
for edge in simple_edges:
graph.add_edge(edge)
all_edge_paths = graph.get_edgepaths()
all_node_paths = graph.get_nodepaths()
self.assertEqual(len(all_node_paths), 15) # should match 6 choose 2 (n!/((n-k)!*k!))
self.assertEqual(all_edge_paths,
[graph.nodepath_to_edgepath(path) for path in all_node_paths])
self.assertEqual(all_node_paths,
[graph.edgepath_to_nodepath(path) for path in all_edge_paths])
def test_graph_remove_edge(self):
n1 = Node('A')
n2 = Node('B')
edge = Edge(n1, n2)
graph = Graph()
graph.add_edge(edge)
graph.remove_edge(edge)
self.assertNotIn(edge, graph.edges)
self.assertIn(n1, graph.nodes)
self.assertIn(n2, graph.nodes)
# not implemented: a node should not be removable if still part of an edge
graph.remove_node(n1)
self.assertNotIn(n1, graph.nodes)