def test_add_all_edges(self):
# Adds an edge to edge-less graph
v, w, e = self.v, self.w, self.e
g = Graph([v, w], [])
g.add_all_edges()
eq_(g.edges(), [e])
# Adds edges between all pairs of vertices in edge-less graph
x = Vertex('x')
e2 = Edge(v, x)
e3 = Edge(w, x)
g = Graph([v, w, x], [])
g.add_all_edges()
eq_(g.edges(), [e, e2, e3])
def test_is_connected(self):
# Returns False for an empty graph
v, w = self.v, self.w
g = Graph([v, w], [])
eq_(g.is_connected(), False)
# Returns True for a complete graph
g.add_all_edges()
eq_(g.is_connected(), True)
# Returns False when a new vertex is added
x = Vertex('x')
g.add_vertex(x)
eq_(g.is_connected(), False)
# Returns True when edge is added to connect it
e2 = Edge(w, x)
g.add_edge(e2)
eq_(g.is_connected(), True)
