def test_topo_sort_knows_what_cycles_are(self):
"""Test that topo_sort fails on cyclic graphs."""
d = DepGraph()
d.add_edge('a', 'b')
d.add_edge('b', 'c')
d.add_edge('c', 'a')
self.assertRaises(HasACycle, d.topo_sort)
assert not d.acyclic
def _check_cycle(self, collection):
"""Raise an exception if there's a relationship cycle."""
d = DepGraph()
for _, fixture in collection:
for dependency, _ in fixture.extract_relationships():
d.add_edge(dependency, fixture.key)
# This does nothing except raise an error if there's a cycle
d.topo_sort()
return d
def test_has_edge_between(self):
"""Test the has_edge_between function."""
d = DepGraph()
#
# a b
# | |
# c -- d e
d.add_edge('a', 'c')
d.add_edge('b', 'd')
d.add_edge('c', 'd')
d.add_node('e')
assert d.has_edge_between('a', 'c')
assert not d.has_edge_between('c', 'a'), 'should not be commutative'
assert not d.has_edge_between('a', 'b'), 'should be edges, not paths'
assert not d.has_edge_between('e', 'd')
def test_ancestors_of(self):
"""Test the ancestors_of function in DepGraph."""
d = DepGraph()
#
# a b
# \ /
# c
# / \
# d e
# |
# f
d.add_edge('a', 'c')
d.add_edge('b', 'c')
d.add_edge('c', 'd')
d.add_edge('c', 'e')
d.add_edge('d', 'f')
l = d.ancestors_of('d')
self.assertCountEqual(l, ['a', 'b', 'c'])
def test_topo_sort(self):
"""Test the topo_sort function of DepGraph."""
d = DepGraph()
#
# a b
# \ /
# c
# |
# d
# / \
# e f
d.add_edge('a', 'c')
d.add_edge('b', 'c')
d.add_edge('c', 'd')
d.add_edge('d', 'e')
d.add_edge('d', 'f')
l = d.topo_sort()
self.assertCountEqual(l, ['a', 'b', 'c', 'd', 'e', 'f'])
assert d.acyclic
