}

  @Test
  public void hasEdgeConnecting_correct() {
    putEdge(N1, N2);
    assertThat(graph.hasEdgeConnecting(EndpointPair.ordered(N1, N2))).isTrue();
  }

  @Test
  public void hasEdgeConnecting_backwards() {
    putEdge(N1, N2);
    assertThat(graph.hasEdgeConnecting(EndpointPair.ordered(N2, N1))).isFalse();
  }

  @Test
  public void hasEdgeConnecting_mismatch() {
    putEdge(N1, N2);