def test_graph_walking_dupes():
"""Make sure _walk_graph() doesn't emit duplicates."""
graph = {'A': [('B', 'b'), ('C', 'c')],
'B': [('D', 'd')],
'C': [('D', 'd')]}
eq_(set(_walk_graph(graph, 'A', set(['A']))),
set([('B', 'b'), ('C', 'c'), ('D', 'd')]))
def test_graph_walking_cycles():
"""Make sure _walk_graph() doesn't get stuck in cycles."""
graph = {'A': [('B', 'b')],
'B': [('C', 'c')],
'C': [('A', 'a')]}
eq_(set(_walk_graph(graph, 'A', set(['A']))),
set([('B', 'b'), ('C', 'c')]))
