public void has_all_the_nodes()
        {
            graph.MenuFor(FakeKeys.Key1).Select(x => x.Key).ShouldHaveTheSameElementsAs(FakeKeys.Key2, FakeKeys.Key3, FakeKeys.Key4);

            var tokens = graph.AllNodes().Select(x => x.Key);

            tokens
            .ShouldHaveTheSameElementsAs(FakeKeys.Key1, FakeKeys.Key2, FakeKeys.Key8, FakeKeys.Key9, FakeKeys.Key10, FakeKeys.Key3, FakeKeys.Key4, FakeKeys.Key5, FakeKeys.Key6, FakeKeys.Key7);
        }