IllegalArgumentException.class, () -> NetworkBuilder.directed().expectedNodeCount(-1));
    assertThat(e).hasMessageThat().contains(ERROR_NEGATIVE_COUNT);
  }

  @Test
  public void createDirected_expectedEdgeCount() {
    MutableNetwork<Integer, String> directedGraph =
        NetworkBuilder.directed().expectedEdgeCount(EDGE_COUNT).build();
    assertThat(directedGraph.addEdge(N1, N2, E12)).isTrue();