def main():
g = Graph()
r = Vertex(g)
r._id = 'root'
A = Vertex(g)
A._id = 'A'
B = Vertex(g)
B._id = 'B'
C = Vertex(g)
C._id = 'C'
D = Vertex(g)
D._id = 'D'
E = Vertex(g)
E._id = 'E'
F = Vertex(g)
F._id = 'F'
G = Vertex(g)
G._id = 'G'
end = Vertex(g)
end._id = 'end'
g.add_edge(r, A)
g.add_edge(r, end)
g.add_edge(A, B)
g.add_edge(A, C)
g.add_edge(B, C)
g.add_edge(C, D)
g.add_edge(C, E)
g.add_edge(D, F)
g.add_edge(E, F)
g.add_edge(F, B)
g.add_edge(F, G)
g.add_edge(G, end)
dt = DominatorTree(r)
assert (r, end) in dt.e
assert (r, A) in dt.e
assert (A, B) in dt.e
assert (A, C) in dt.e
assert (A, C) in dt.e
assert (C, D) in dt.e
assert (C, E) in dt.e
assert (C, F) in dt.e
assert (F, G) in dt.e
g.entry = r
