def __is_valid_graph(self, edges: Iterable[Tuple[int, int]]) -> str:
"""Test graph and return True if it is valid."""
try:
g = Graph(edges)
except (TypeError, ValueError):
return "wrong format"
if not g.edges:
return "is an empty graph"
if not g.is_connected():
return "is not a close chain"
if not is_planar(g):
return "is not a planar chain"
if g.has_cut_link():
return "has cut link"
try:
external_loop_layout(g, True)
except ValueError as error:
return str(error)
for h in self.collections:
if g.is_isomorphic(h):
return f"is isomorphic with: {h.edges}"
return ""
def test_graph_basic(self):
"""Test 'graph' libraries."""
g1 = Graph([(0, 1), (0, 4), (1, 5), (2, 3), (2, 4), (3, 5), (4, 5)])
self.assertFalse(g1.is_degenerate())
self.assertTrue(g1.is_connected())
self.assertEqual(1, g1.dof())