assertThat(network.edges()).containsExactly(10);
    assertThat(network.incidentNodes(10)).isEqualTo(EndpointPair.ordered("A", "B"));
  }

  @Test
  public void immutableNetworkBuilder_putEdgeFromEndpointPair() {
    ImmutableNetwork<String, Integer> network =
        NetworkBuilder.directed()
            .<String, Integer>immutable()
            .addEdge(EndpointPair.ordered("A", "B"), 10)