public void AddsANewEdges()
            {
                //by value
                EdgeListNode <int> node = new EdgeListNode <int>(1);

                node.AddEdgeTo(1);
                bool added = node.HasEdgeTo(1);

                Assert.True(added);

                //by node
                node = new EdgeListNode <int>(1);
                node.AddEdgeTo(node);
                added = node.HasEdgeTo(1);
                Assert.True(added);
            }
            public void DetectsNegativesCases()
            {
                //by value
                EdgeListNode <int> node = new EdgeListNode <int>(1);

                node.AddEdgeTo(2);
                bool hasEdgeToValue = node.HasEdgeTo(5);

                Assert.False(hasEdgeToValue);

                //by node
                node = new EdgeListNode <int>(1);
                EdgeListNode <int> neighbour = new EdgeListNode <int>(5);
                bool hasEdgeToNode           = node.HasEdgeTo(neighbour);

                Assert.False(hasEdgeToNode);
            }
            public void DoesNotRetrieveNonExistingEdges()
            {
                //by value
                EdgeListNode <int> node = new EdgeListNode <int>(1);

                node.AddEdgeTo(2);
                bool hasEdgeToValue = node.HasEdgeTo(5);

                Assert.False(hasEdgeToValue);

                //by node
                node = new EdgeListNode <int>(1);
                EdgeListNode <int> neighbour = new EdgeListNode <int>(5);
                bool hasEdgeToNode           = node.HasEdgeTo(neighbour);

                Assert.False(hasEdgeToNode);
            }
            public void DetectsPositiveCases()
            {
                //by value
                EdgeListNode <int> node = new EdgeListNode <int>(1);

                node.AddEdgeTo(2);
                bool hasEdgeToValue = node.HasEdgeTo(2);

                Assert.True(hasEdgeToValue);

                //by node
                node = new EdgeListNode <int>(1);
                EdgeListNode <int> neighbour = new EdgeListNode <int>(2);

                node.AddEdgeTo(neighbour);
                bool hasEdgeToNode = node.HasEdgeTo(neighbour);

                Assert.True(hasEdgeToNode);
            }