def test_dijkstra(self):
g = Graph()
for i in range(4):
g.add_vertex(i)
g.add_edge(0, 1, 1)
g.add_edge(0, 2, 2)
g.add_edge(1, 3, 2)
g.add_edge(2, 3, 2)
def test_add_vertex(self):
g = Graph()
g.add_vertex(1)
assert len(g.vertices) == 1
assert 1 in g.vertices
assert g.vertices[1] == {}
g.add_vertex(2)
assert len(g.vertices) == 2
assert 2 in g.vertices
g.add_vertex(1)
assert len(g.vertices) == 2
assert 1 in g.vertices
assert g.vertices[1] == {}
# Let's try non-numbers
g.add_vertex('A')
assert len(g.vertices) == 3
assert 'A' in g.vertices
assert g.vertices['A'] == {}
def test_remove(self):
g = Graph()
g.add_vertex(1)
g.add_vertex(2)
g.add_vertex(3)
g.add_edge(1, 2)
g.add_edge(1, 3)
# Should be removed
g.remove_edge(1, 2)
assert 2 not in g.vertices[1]
assert 3 in g.vertices[1]
assert 1 not in g.vertices[2]
assert 3 not in g.vertices[2]
assert 1 not in g.vertices[3]
assert 2 not in g.vertices[3]
# Let's reset that and add more things that link to 3
g.add_edge(1, 2)
g.add_edge(2, 3)
assert 3 in g.vertices[1]
assert 3 in g.vertices[2]
# And remove 3
g.remove_vertex(3)
# It should stop existing, even in previous adjacincies
assert 3 not in g.vertices[1]
assert 3 not in g.vertices[2]
assert 3 not in g.vertices
# Delete something that doesn't exist,
with self.assertRaises(ValueError):
g.remove_vertex(6)
# Let's make 1 not exist
g.remove_vertex(1)
with self.assertRaises(ValueError):
g.add_edge(2, 1)
assert 1 not in g.vertices
# Adding edges
with self.assertRaises(ValueError):
g.add_edge(2, 1)
with self.assertRaises(ValueError):
g.add_edge(1, 2)
# Removing edges that can't exist, src and dest
with self.assertRaises(ValueError):
g.remove_edge(5, 6)
with self.assertRaises(ValueError):
g.remove_edge(1, 6)
def test_adjacency(self):
g = Graph()
g.add_vertex(1)
g.add_vertex(2)
# Edge should exist only in 1
g.add_edge(1, 2)
assert 2 in g.vertices[1]
assert 1 not in g.vertices[2]
# Edge should exist only in 1
g.add_edge(2, 1)
assert 2 in g.vertices[1]
assert 1 in g.vertices[2]
# 4 does not exist yet; should throw error
with self.assertRaises(ValueError):
g.add_edge(1, 4)
assert 2 in g.vertices[1]
assert 4 not in g.vertices[1]
# Let's try a nonexistent source
with self.assertRaises(ValueError):
g.add_edge(5, 4)
# Vtx 1 should now have an extra one
g.add_vertex(3)
g.add_edge(1,3)
assert 2 in g.vertices[1]
assert 3 in g.vertices[1]
def test_cyclic_detection(self):
g = Graph()
g.add_vertex(1)
g.add_vertex(2)
g.add_vertex(3)
g.add_vertex(4)
assert g.cycle_detect() is False
# Let's add a straight line
g.add_edge(1, 2)
g.add_edge(2, 3)
assert g.cycle_detect() is False
# move from 3 to 1
g.add_edge(3, 1)
assert g.cycle_detect() is True
g.remove_edge(3, 1)
# Looping 4 to 4
g.add_edge(4, 4)
assert g.cycle_detect() is True
# Removed 4 to 4
g.remove_edge(4, 4)
assert g.cycle_detect() is False
def test_bfs(self):
g = Graph()
g.add_vertex(1)
g.add_vertex(2)
g.add_vertex(3)
g.add_edge(1,2)
# We should only have 1 to 2 due to it being directed
assert g.bfs(1, 1) is True
assert g.bfs(1, 2) is True
assert g.bfs(1, 3) is False
assert g.bfs(2, 1) is False
assert g.bfs(2, 2) is True
assert g.bfs(2, 3) is False
assert g.bfs(3, 1) is False
assert g.bfs(3, 2) is False
assert g.bfs(3, 3) is True
g.add_edge(3, 1)
# Copy of previous, save for 3 to 1, which leads to 2 as well
assert g.bfs(1, 1) is True
assert g.bfs(1, 2) is True
assert g.bfs(1, 3) is False
assert g.bfs(2, 1) is False
assert g.bfs(2, 2) is True
assert g.bfs(2, 3) is False
assert g.bfs(3, 1) is True
assert g.bfs(3, 2) is True
assert g.bfs(3, 3) is True