g1.putEdge(N1, N2);
    g1.putEdge(N3, N1);

    // for g2, add 3->1 first, then 1->2
    g2.putEdge(N3, N1);
    g2.putEdge(N1, N2);

    assertThat(g1).isEqualTo(g2);
  }

  @Test
  public void equivalent_edgeDirectionsDiffer() {
    graph.putEdge(N1, N2);

    MutableGraph<Integer> g2 = createGraph(edgeType);
    g2.putEdge(N2, N1);

    switch (edgeType) {

    assertThat(graph.predecessors(N2)).containsExactly(N1);
    assertThat(graphAsMutableGraph.removeEdge(N1, N2)).isTrue();
    assertThat(graphAsMutableGraph.removeEdge(N1, N2)).isFalse();
    assertThat(graph.successors(N1)).isEmpty();
    assertThat(graph.predecessors(N2)).isEmpty();
  }

  @Test
  public void removeEdge_oneOfMany() {
    assume().that(graphIsMutable()).isTrue();

    putEdge(N1, N2);

gin-top:-.25rem!important}.mr-n1,.mx-n1{margin-right:-.25rem!important}.mb-n1,.my-n1{margin-bottom:-.25rem!important}.ml-n1,.mx-n1{margin-left:-.25rem!important}.m-n2{margin:-.5rem!important}.mt-n2,.my-n2{margin-top:-.5rem!important}.mr-n2,.mx-n2{margin-right:-.5rem!important}.mb-n2,.my-n2{margin-bottom:-.5rem!important}.ml-n2,.mx-n2{margin-left:-.5rem!important}.m-n3{margin:-1rem!important}.mt-n3,.my-n3{margin-top:-1rem!important}.mr-n3,.mx-n3{margin-right:-1rem!important}.mb-n3,.my-n3{margin-b...

    }
  }

  /** Returns the product of {@code n1} exclusive through {@code n2} inclusive. */
  @SuppressWarnings("UseCorrectAssertInTests") // TODO(b/345814817): Remove or convert assertion.
  private static BigInteger oldSlowFactorial(int n1, int n2) {
    assert n1 <= n2;
    if (IntMath.log2(n2, CEILING) * (n2 - n1) < Long.SIZE - 1) {
      // the result will definitely fit into a long
      long result = 1;

        .build();
  }

  @Override
  final void addNode(Integer n) {
    graphAsMutableGraph.addNode(n);
  }

  @Override
  final void putEdge(Integer n1, Integer n2) {
    graphAsMutableGraph.putEdge(n1, n2);
  }

  public void testFirstNonNull_withNonNull() {
    String s1 = "foo";
    String s2 = MoreObjects.firstNonNull(s1, "bar");
    assertSame(s1, s2);

    Long n1 = 42L;
    Long n2 = MoreObjects.firstNonNull(null, n1);
    assertSame(n1, n2);

    Boolean b1 = true;
    Boolean b2 = MoreObjects.firstNonNull(b1, null);
    assertSame(b1, b2);
  }

  public void testFirstNonNull_throwsNullPointerException() {

  public void testFirstNonNull_withNonNull() {
    String s1 = "foo";
    String s2 = MoreObjects.firstNonNull(s1, "bar");
    assertSame(s1, s2);

    Long n1 = 42L;
    Long n2 = MoreObjects.firstNonNull(null, n1);
    assertSame(n1, n2);

    Boolean b1 = true;
    Boolean b2 = MoreObjects.firstNonNull(b1, null);
    assertSame(b1, b2);
  }

  public void testFirstNonNull_throwsNullPointerException() {

  }

  @Override
  final void addNode(Integer n) {
    graphBuilder.addNode(n);
    graph = graphBuilder.build();
  }

  @Override
  final void putEdge(Integer n1, Integer n2) {
    graphBuilder.putEdge(n1, n2);
    graph = graphBuilder.build();
  }

    expectedClosure.putEdge(N2, N1);
    expectedClosure.putEdge(N2, N2);
    expectedClosure.putEdge(N2, N3);
    expectedClosure.putEdge(N2, N4);
    expectedClosure.putEdge(N3, N1);
    expectedClosure.putEdge(N3, N2);
    expectedClosure.putEdge(N3, N3);
    expectedClosure.putEdge(N3, N4);
    expectedClosure.putEdge(N4, N1);
    expectedClosure.putEdge(N4, N2);
    expectedClosure.putEdge(N4, N3);
    expectedClosure.putEdge(N4, N4);

    addEdge(N1, N2, E12);
    assertThat(network.successors(N1)).containsExactly(N2);
    assertThat(network.successors(N2)).containsExactly(N1);
  }

  @Test
  public void inDegree_oneEdge() {
    addEdge(N1, N2, E12);
    assertThat(network.inDegree(N2)).isEqualTo(1);
    assertThat(network.inDegree(N1)).isEqualTo(1);
  }

  @Test
  public void outDegree_oneEdge() {
    addEdge(N1, N2, E12);