// Direction of the added edge is correctly handled
    assertThat(network.edgesConnecting(N3, N2)).isEmpty();
  }

  @Test
  public void addEdge_selfLoop_allowed() {
    assume().that(graphIsMutable()).isTrue();
    assume().that(network.allowsSelfLoops()).isTrue();

    assertThat(networkAsMutableNetwork.addEdge(N1, N1, E11)).isTrue();

    // Direction of the added edge is correctly handled
    assertThat(network.edgesConnecting(N3, N2)).isEmpty();
  }

  @Test
  public void addEdge_selfLoop_allowed() {
    assume().that(graphIsMutable()).isTrue();
    assume().that(network.allowsSelfLoops()).isTrue();

    assertThat(networkAsMutableNetwork.addEdge(N1, N1, E11)).isTrue();