def test_breadth_first_3_el():
graph = Graph()
start = graph.add_node('spam')
middle = graph.add_node('bacon')
end = graph.add_node('eggs')
graph.add_edge(start, end)
graph.add_edge(start, middle, 2)
assert graph.depth_first(start) == ['spam', 'bacon', 'eggs']
def test_breadth_first_few_edges():
graph = Graph()
a = graph.add_node('A')
b = graph.add_node('B')
c = graph.add_node('C')
g = graph.add_node('G')
d = graph.add_node('D')
e = graph.add_node('E')
h = graph.add_node('H')
f = graph.add_node('F')
graph.add_edge(a, d)
graph.add_edge(a, b)
graph.add_edge(b, c)
graph.add_edge(c, g)
graph.add_edge(d, f)
graph.add_edge(d, h)
graph.add_edge(d, e)
graph.add_edge(h, f)
assert graph.depth_first(a) == ['A', 'B', 'C', 'G', 'D', 'E', 'H', 'F']
def test_breadth_1_edge():
graph = Graph()
first = graph.add_node('spam')
second = graph.add_node('bacon')
graph.add_edge(first, second)
assert graph.depth_first(first) == ['spam', 'bacon']