fix iteration over edges

Hong-Phuc Bui

2 days ago 9309589ff6fe3f61abd61263f61eb890141f6491

 stundenplan/src/graphdemo_tests.py

@@ -29,11 +29,14 @@
        edges = [
            "1-2", "1-3", "2-3", "2-4"
        ]
        edge_count = []
        def action(a, b):
            (s,e) = (a,b) if a < b else (b,a)
            edge = f"{s}-{e}"
            edge_count.append(edge)
            self.assertTrue(edge in edges)
        g.for_each_edges(action)
        self.assertEqual(len(edge_count), len(edges))

    def test_iterate_all_vertices(self):
        g = Graph()
@@ -48,6 +51,18 @@
        self.assertListEqual(sorted(vertices), expected)
        pass

    def test_iterate_all_vertices_lambda(self):
        g = Graph()
        g.add_edge(1, 2)
        g.add_edge(1, 3)
        g.add_edge(2, 3)
        g.add_edge(2, 4)
        vertices = []
        g.for_each_vertices(lambda v : print(f"visit {v}"))
        print(vertices)
        pass


    def test_iterate_neighbor_vertex(self):
        g = Graph()
        g.add_edge(1, 2)