g2.addEdge(N1, N1, E11);

    assertThat(network).isNotEqualTo(g2);
  }

  // Node/edge sets are the same, but node/edge connections differ.
  @Test
  public void equivalent_connectionsDiffer() {
    network.addEdge(N1, N2, E12);
    network.addEdge(N1, N3, E13);

    MutableNetwork<Integer, String> g2 = createNetwork(edgeType);

    g2.addEdge(N1, N1, E11);

    assertThat(network).isNotEqualTo(g2);
  }

  // Node/edge sets are the same, but node/edge connections differ.
  @Test
  public void equivalent_connectionsDiffer() {
    network.addEdge(N1, N2, E12);
    network.addEdge(N1, N3, E13);

    MutableNetwork<Integer, String> g2 = createNetwork(edgeType);