assertThat(hasCycle(directedGraph)).isFalse();
    assertThat(hasCycle(undirectedGraph)).isFalse();
  }

  @Test
  public void hasCycle_isolatedNodes() {
    for (MutableGraph<Integer> graph : graphsToTest) {
      graph.addNode(1);
      graph.addNode(2);
    }
    assertThat(hasCycle(directedGraph)).isFalse();
    assertThat(hasCycle(undirectedGraph)).isFalse();
  }

  @Test

    assertThat(future.set(99)).isFalse();
    assertThat(future.setException(new IndexOutOfBoundsException())).isFalse();
    assertThat(future.setFuture(new AbstractFuture<Integer>() {})).isFalse();
    assertThat(future.setFuture(immediateFuture(99))).isFalse();
  }

  private static void assertCannotCancel(AbstractFuture<Integer> future) {
    assertThat(future.cancel(true)).isFalse();

    putEdge(N1, N2);
    assertThat(graph.hasEdgeConnecting(EndpointPair.ordered(N2, N1))).isFalse();
  }

  @Test
  public void hasEdgeConnecting_mismatch() {
    putEdge(N1, N2);
    assertThat(graph.hasEdgeConnecting(EndpointPair.unordered(N1, N2))).isFalse();
    assertThat(graph.hasEdgeConnecting(EndpointPair.unordered(N2, N1))).isFalse();
  }

  @Test
  public void adjacentNodes_selfLoop() {

    assertThat(graphAsMutableGraph.addNode(N1)).isFalse();
    assertThat(graph.nodes()).containsExactlyElementsIn(nodes);
  }

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

    putEdge(N1, N2);
    putEdge(N4, N1);
    assertThat(graphAsMutableGraph.removeNode(N1)).isTrue();
    assertThat(graphAsMutableGraph.removeNode(N1)).isFalse();

    assertThat(listEqualsArray).isFalse();
    assertThat(Booleans.asList(ARRAY_FALSE).equals(null)).isFalse();
    assertThat(Booleans.asList(ARRAY_FALSE).equals(Booleans.asList(ARRAY_FALSE_TRUE))).isFalse();
    assertThat(Booleans.asList(ARRAY_FALSE_FALSE).equals(Booleans.asList(ARRAY_FALSE_TRUE)))
        .isFalse();
    assertEquals(1, Booleans.asList(ARRAY_FALSE_TRUE).lastIndexOf(true));

    assertThat(listEqualsArray).isFalse();
    assertThat(Booleans.asList(ARRAY_FALSE).equals(null)).isFalse();
    assertThat(Booleans.asList(ARRAY_FALSE).equals(Booleans.asList(ARRAY_FALSE_TRUE))).isFalse();
    assertThat(Booleans.asList(ARRAY_FALSE_FALSE).equals(Booleans.asList(ARRAY_FALSE_TRUE)))
        .isFalse();
    assertEquals(1, Booleans.asList(ARRAY_FALSE_TRUE).lastIndexOf(true));

    double y1 = 3.4;
    double slope = Double.MIN_VALUE;
    LinearTransformation transformation = LinearTransformation.mapping(x1, y1).withSlope(slope);
    assertThat(transformation.isVertical()).isFalse();
    assertThat(transformation.isHorizontal()).isFalse();
    assertThat(transformation.slope()).isWithin(ALLOWED_ERROR).of(slope);
    // Note that we cannot test the actual mapping of points, as the results will be unreliable due

    double y1 = 3.4;
    double slope = Double.MIN_VALUE;
    LinearTransformation transformation = LinearTransformation.mapping(x1, y1).withSlope(slope);
    assertThat(transformation.isVertical()).isFalse();
    assertThat(transformation.isHorizontal()).isFalse();
    assertThat(transformation.slope()).isWithin(ALLOWED_ERROR).of(slope);
    // Note that we cannot test the actual mapping of points, as the results will be unreliable due

    CompactHashSet<Integer> set = CompactHashSet.create();
    assertThat(set.needsAllocArrays()).isTrue();
    assertThat(set.elements).isNull();

    set.add(1);
    assertThat(set.needsAllocArrays()).isFalse();
    assertThat(set.elements).hasLength(CompactHashing.DEFAULT_SIZE);
  }

  public void testAllocArraysExpectedSize() {
    for (int i = 0; i <= CompactHashing.DEFAULT_SIZE; i++) {

    assume().that(graphIsMutable()).isTrue();

    addEdge(N1, N2, E12);
    ImmutableSet<String> edges = ImmutableSet.copyOf(network.edges());
    assertThat(networkAsMutableNetwork.addEdge(N1, N2, E12)).isFalse();
    assertThat(network.edges()).containsExactlyElementsIn(edges);
  }

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