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

    Set<Integer> nodes = graph.nodes();
    assertThrows(UnsupportedOperationException.class, () -> nodes.add(N2));
    addNode(N1);
    assertThat(graph.nodes()).containsExactlyElementsIn(nodes);
  }

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

    addNode(N1);

  private static <R, C, V> void validateViewOrdering(Table<R, C, V> original, Table<R, C, V> copy) {
    assertThat(copy.cellSet()).containsExactlyElementsIn(original.cellSet()).inOrder();
    assertThat(copy.rowKeySet()).containsExactlyElementsIn(original.rowKeySet()).inOrder();
    assertThat(copy.values()).containsExactlyElementsIn(original.values()).inOrder();
  }

  public void testCopyOf() {

    while (!q.isEmpty()) {
      assertThat(q).containsExactlyElementsIn(contents);
      Integer next = q.pollFirst();
      contents.remove(next);
      assertThat(q).containsExactlyElementsIn(contents);
      for (int i = 0; i <= size; i++) {
        q.add(i);
        contents.add(i);
        assertThat(q).containsExactlyElementsIn(contents);
        q.add(next);
        contents.add(next);

    while (!q.isEmpty()) {
      assertThat(q).containsExactlyElementsIn(contents);
      Integer next = q.pollFirst();
      contents.remove(next);
      assertThat(q).containsExactlyElementsIn(contents);
      for (int i = 0; i <= size; i++) {
        q.add(i);
        contents.add(i);
        assertThat(q).containsExactlyElementsIn(contents);
        q.add(next);
        contents.add(next);

    ImmutableSortedSet<String> set = ImmutableSortedSet.copyOf(strings);
    sort(strings);
    for (int i = 0; i < strings.length; i++) {
      assertThat(set.headSet(strings[i], true))
          .containsExactlyElementsIn(sortedNumberNames(0, i + 1))
          .inOrder();
    }
  }

  public void testHeadSetExclusive() {
    String[] strings = NUMBER_NAMES.toArray(new String[0]);

        assertThat(navigableMap.headMap(key, inclusive).entrySet())
            .containsExactlyElementsIn(expected.headMap(key, inclusive).entrySet())
            .inOrder();
        assertThat(navigableMap.tailMap(key, inclusive).entrySet())
            .containsExactlyElementsIn(expected.tailMap(key, inclusive).entrySet())
            .inOrder();

    ImmutableSortedSet<String> set = ImmutableSortedSet.copyOf(strings);
    sort(strings);
    for (int i = 0; i < strings.length; i++) {
      assertThat(set.headSet(strings[i], true))
          .containsExactlyElementsIn(sortedNumberNames(0, i + 1))
          .inOrder();
    }
  }

  public void testHeadSetExclusive() {
    String[] strings = NUMBER_NAMES.toArray(new String[0]);

    addNode(N1);
    ImmutableSet<Integer> nodes = ImmutableSet.copyOf(graph.nodes());
    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);

    assertThrows(UnsupportedOperationException.class, () -> edgesConnecting.add(E23));
    network.addEdge(N1, N2, E12);
    assertThat(networkForTest.edgesConnecting(N1, N2)).containsExactlyElementsIn(edgesConnecting);
  }

  @Test
  public void edgesConnecting_oneEdge() {
    network.addEdge(N1, N2, E12);
    assertThat(networkForTest.edgesConnecting(N1, N2)).containsExactly(E12);

      assertThat(location.scanResources()).containsExactlyElementsIn(resources);
    }
  }

  public void testLocationsFrom_idempotentLocations() {
    ImmutableSet<ClassPath.LocationInfo> locations =
        ClassPath.locationsFrom(getClass().getClassLoader());
    assertThat(ClassPath.locationsFrom(getClass().getClassLoader()))
        .containsExactlyElementsIn(locations);
  }