def multiplePathsTest():
"""This method checks that the algorithm returns
the correct number of shortest paths, when there
are more than one way of reaching the end node.
"""
g = MyGraph()
v0 = GraphVertex("v0")
v1 = GraphVertex("v1")
v2 = GraphVertex("v2")
v3 = GraphVertex("v3")
g.insertVertex(v0)
g.insertVertex(v1)
g.insertVertex(v2)
g.insertVertex(v3)
e0 = GraphEdge("e0", 1)
e1 = GraphEdge("e1", 1)
e2 = GraphEdge("e2", 1)
e3 = GraphEdge("e3", 1)
g.insertEdge(v0, v3, e0)
g.insertEdge(v0, v1, e1)
g.insertEdge(v1, v2, e2)
g.insertEdge(v3, v2, e3)
ret = numShortestPaths(g, v0, v2)
assert ret == 2
def exceptionsTest():
"""This method checks that the numShortestPaths.py will
throw a InvalidInputException when the input nodes or graph
are not valid.
"""
with pytest.raises(InvalidInputException):
g = v0 = v1 = None
# raises exception because graph and vertices are None.
numShortestPaths(g, v0, v1)
with pytest.raises(InvalidInputException):
g = MyGraph()
v0 = GraphVertex("v0")
v1 = GraphVertex("v1")
e0 = GraphEdge("e0", 1)
# raises exception because v0, v1 are not vertices of g.
numShortestPaths(g, v0, v1)
def singleVertexTest():
"""This method tests a special case, and checks that
the number of shortest paths in a graph with one vertex
and no edges is 1.
"""
g = MyGraph()
a = GraphVertex("a")
g.insertVertex(a)
assert numShortestPaths(g, a, a) == 1, "Error"
def complicatedPathsTest():
"""This method checks that the algorithm returns
the correct number of shortest paths in the graph, when
there are numerous complicated paths reaching the end
node, as well as paths that don't lead to the end node.
"""
g = MyGraph()
start = GraphVertex("start")
A = GraphVertex("A")
B = GraphVertex("B")
C = GraphVertex("C")
D = GraphVertex("D")
E = GraphVertex("E")
F = GraphVertex("F")
G = GraphVertex("G")
H = GraphVertex("H")
end = GraphVertex("end")
g.insertVertex(start)
g.insertVertex(A)
g.insertVertex(B)
g.insertVertex(C)
g.insertVertex(D)
g.insertVertex(E)
g.insertVertex(F)
g.insertVertex(G)
g.insertVertex(H)
g.insertVertex(end)
e0 = GraphEdge("e0", 1)
e1 = GraphEdge("e1", 1)
e2 = GraphEdge("e2", 1)
e3 = GraphEdge("e3", 1)
e4 = GraphEdge("e4", 1)
e5 = GraphEdge("e5", 1)
e6 = GraphEdge("e6", 1)
e7 = GraphEdge("e7", 1)
e8 = GraphEdge("e8", 1)
e9 = GraphEdge("e9", 1)
e10 = GraphEdge("e10", 1)
g.insertEdge(start, A, e0)
g.insertEdge(start, B, e1)
g.insertEdge(start, C, e2)
g.insertEdge(A, D, e3)
g.insertEdge(D, H, e4)
g.insertEdge(D, G, e5)
g.insertEdge(B, E, e6)
g.insertEdge(B, F, e7)
g.insertEdge(G, end, e8)
g.insertEdge(E, end, e9)
g.insertEdge(F, end, e10)
ret = numShortestPaths(g, start, end)
assert ret == 2
def singlePathTest():
"""This method checks that the algorithm returns the
correct number of shortest path, which is 1, for a
graph with only two nodes, start and end.
"""
g = MyGraph()
v0 = GraphVertex("start")
v1 = GraphVertex("end")
g.insertVertex(v0)
g.insertVertex(v1)
e0 = GraphEdge("single_edge", 1)
g.insertEdge(v0, v1, e0)
assert numShortestPaths(g, v0, v1) == 1, "single-path test failed."
def test1():
g = MyGraph()
v0 = GraphVertex("v0")
v1 = GraphVertex("v1")
v2 = GraphVertex("v2")
g.insertVertex(v0)
g.insertVertex(v1)
g.insertVertex(v2)
e0 = GraphEdge("e0", 1)
e1 = GraphEdge("e1", 1)
e2 = GraphEdge("e2", 1)
g.insertEdge(v0, v2, e0)
g.insertEdge(v0, v1, e1)
g.insertEdge(v1, v2, e2)
ret = numShortestPaths(g, v0, v2)
assert ret == 1
def test1():
"""This method is an example test that checks outputs of
numShortestPaths.py for a graph with three vertices.
"""
g = MyGraph()
v0 = GraphVertex("v0")
v1 = GraphVertex("v1")
v2 = GraphVertex("v2")
g.insertVertex(v0)
g.insertVertex(v1)
g.insertVertex(v2)
e0 = GraphEdge("e0", 1)
e1 = GraphEdge("e1", 1)
e2 = GraphEdge("e2", 1)
g.insertEdge(v0, v2, e0)
g.insertEdge(v0, v1, e1)
g.insertEdge(v1, v2, e2)
ret = numShortestPaths(g, v0, v2)
assert ret == 1