public void ContainsVertex()
{
var graph = new TransitionFactoryImplicitGraph <CloneableTestVertex, Edge <CloneableTestVertex> >();
var vertex1 = new CloneableTestVertex("1");
var vertex2 = new CloneableTestVertex("2");
var otherVertex1 = new CloneableTestVertex("1");
var vertex3 = new CloneableTestVertex("3");
var vertex4 = new CloneableTestVertex("4");
var edge34 = new Edge <CloneableTestVertex>(vertex3, vertex4);
Assert.IsFalse(graph.ContainsVertex(vertex1));
Assert.IsFalse(graph.ContainsVertex(vertex2));
Assert.IsFalse(graph.ContainsVertex(otherVertex1));
Assert.IsFalse(graph.ContainsVertex(vertex3));
Assert.IsFalse(graph.ContainsVertex(vertex4));
var factory1 = new TestTransitionFactory <CloneableTestVertex>(vertex1, Enumerable.Empty <Edge <CloneableTestVertex> >());
graph.AddTransitionFactory(factory1);
Assert.IsFalse(graph.ContainsVertex(vertex1)); // Not explored yet
Assert.IsFalse(graph.ContainsVertex(vertex2));
Assert.IsFalse(graph.ContainsVertex(otherVertex1));
Assert.IsFalse(graph.ContainsVertex(vertex3));
Assert.IsFalse(graph.ContainsVertex(vertex4));
// ReSharper disable once ReturnValueOfPureMethodIsNotUsed
graph.OutEdges(vertex1);
Assert.IsTrue(graph.ContainsVertex(vertex1));
Assert.IsFalse(graph.ContainsVertex(vertex2));
Assert.IsFalse(graph.ContainsVertex(otherVertex1));
Assert.IsFalse(graph.ContainsVertex(vertex3));
Assert.IsFalse(graph.ContainsVertex(vertex4));
var factory2 = new TestTransitionFactory <CloneableTestVertex>(vertex2, Enumerable.Empty <Edge <CloneableTestVertex> >());
graph.AddTransitionFactory(factory2);
Assert.IsTrue(graph.ContainsVertex(vertex1));
Assert.IsFalse(graph.ContainsVertex(vertex2)); // Not explored yet
Assert.IsFalse(graph.ContainsVertex(otherVertex1));
Assert.IsFalse(graph.ContainsVertex(vertex3));
Assert.IsFalse(graph.ContainsVertex(vertex4));
// ReSharper disable once ReturnValueOfPureMethodIsNotUsed
graph.OutEdges(vertex2);
Assert.IsTrue(graph.ContainsVertex(vertex1));
Assert.IsTrue(graph.ContainsVertex(vertex2));
Assert.IsFalse(graph.ContainsVertex(otherVertex1));
Assert.IsFalse(graph.ContainsVertex(vertex3));
Assert.IsFalse(graph.ContainsVertex(vertex4));
var factoryOther1 = new TestTransitionFactory <CloneableTestVertex>(otherVertex1, Enumerable.Empty <Edge <CloneableTestVertex> >());
graph.AddTransitionFactory(factoryOther1);
Assert.IsTrue(graph.ContainsVertex(vertex1));
Assert.IsTrue(graph.ContainsVertex(vertex2));
Assert.IsFalse(graph.ContainsVertex(otherVertex1)); // Not explored yet
Assert.IsFalse(graph.ContainsVertex(vertex3));
Assert.IsFalse(graph.ContainsVertex(vertex4));
// ReSharper disable once ReturnValueOfPureMethodIsNotUsed
graph.OutEdges(otherVertex1);
Assert.IsTrue(graph.ContainsVertex(vertex1));
Assert.IsTrue(graph.ContainsVertex(vertex2));
Assert.IsTrue(graph.ContainsVertex(otherVertex1));
Assert.IsFalse(graph.ContainsVertex(vertex3));
Assert.IsFalse(graph.ContainsVertex(vertex4));
var factory3 = new TestTransitionFactory <CloneableTestVertex>(vertex3, new[] { edge34 });
graph.AddTransitionFactory(factory3);
Assert.IsTrue(graph.ContainsVertex(vertex1));
Assert.IsTrue(graph.ContainsVertex(vertex2));
Assert.IsTrue(graph.ContainsVertex(otherVertex1));
Assert.IsFalse(graph.ContainsVertex(vertex3)); // Not explored yet
Assert.IsFalse(graph.ContainsVertex(vertex4));
// ReSharper disable once ReturnValueOfPureMethodIsNotUsed
graph.OutEdges(vertex3);
Assert.IsTrue(graph.ContainsVertex(vertex1));
Assert.IsTrue(graph.ContainsVertex(vertex2));
Assert.IsTrue(graph.ContainsVertex(otherVertex1));
Assert.IsTrue(graph.ContainsVertex(vertex3));
Assert.IsTrue(graph.ContainsVertex(vertex4)); // Discovered when requesting vertex3
}