def test_simple_pass(self):
     """Cyclic graphs are connected 2A and 2E."""
     g = UG()
     g.addpath(0, 1)
     g.addpath(1, 2)
     g.addpath(2, 0)
     self.assertTrue(g.checkconnectivity_2A())
     self.assertTrue(g.checkconnectivity_2E())
 def test_simple_fail(self):
     """A cycle makes a graph 2E, but not necessarily 2A."""
     g = UG()
     g.addpath(0, 1)
     g.addpath(1, 2)
     g.addpath(2, 0)
     g.addpath(3, 0)
     self.assertFalse(g.checkconnectivity_2A())
     self.assertTrue(g.checkconnectivity_2E())
 def test_textbook_fail(self):
     """Textbook example modified to be not 2E or 2A connected."""
     g = UG()
     g.addpath('a', 'b')
     g.addpath('b', 'e')
     g.addpath('e', 'd')
     g.addpath('d', 'c')
     g.addpath('e', 'f')
     g.addpath('e', 'h')
     g.addpath('f', 'g')
     g.addpath('f', 'i')
     g.addpath('i', 'j')
     g.addpath('i', 'm')
     g.addpath('m', 'k')
     g.addpath('k', 'l')
     self.assertFalse(g.checkconnectivity_2A())  # False
     self.assertFalse(g.checkconnectivity_2E())  # False
 def test_textbook_pass2E(self):
     """Textbook example of 2E connectedness."""
     g = UG()
     g.addpath('a', 'b')
     g.addpath('b', 'e')
     g.addpath('e', 'd')
     g.addpath('d', 'c')
     g.addpath('e', 'f')
     g.addpath('e', 'h')
     g.addpath('f', 'g')
     g.addpath('f', 'i')
     g.addpath('i', 'j')
     g.addpath('i', 'm')
     g.addpath('m', 'k')
     g.addpath('k', 'l')
     g.addpath('g', 'h')
     self.assertFalse(g.checkconnectivity_2A())  # False
     self.assertTrue(g.checkconnectivity_2E())  # True
 def test_trivial_pass_zero(self):
     """Graphs with zero nodes are automatically very connected."""
     g = UG()
     self.assertTrue(g.checkconnectivity_2A())
     self.assertTrue(g.checkconnectivity_2E())
 def test_trivial_fail(self):
     """With just two nodes and one path, this isn't very connected."""
     g = UG()
     g.addpath(0, 1)
     self.assertFalse(g.checkconnectivity_2A())
     self.assertFalse(g.checkconnectivity_2E())
 def test_trivial_pass_one(self):
     """Graphs with one node are automatically very connected."""
     g = UG()
     g.addnode(42)
     self.assertTrue(g.checkconnectivity_2A())
     self.assertTrue(g.checkconnectivity_2E())