* need to guard against those conditions, you should employ other file-level synchronization.
   *
   * <p><b>Warning:</b> If {@code to} represents an existing file, that file will be overwritten
   * with the contents of {@code from}. If {@code to} and {@code from} refer to the <i>same</i>
   * file, the contents of that file will be deleted.
   *
   * <p><b>{@link java.nio.file.Path} equivalent:</b> {@link

  }

  @Test
  public void undirectedGraph() {
    graph = ValueGraphBuilder.undirected().allowsSelfLoops(true).build();
    graph.putEdgeValue(1, 2, "valueA");
    graph.putEdgeValue(2, 1, "valueB"); // overwrites valueA in undirected case
    graph.putEdgeValue(2, 3, "valueC");
    graph.putEdgeValue(4, 4, "valueD");

    assertThat(graph.edgeValueOrDefault(1, 2, null)).isEqualTo("valueB");

        ValueGraphBuilder.undirected().allowsSelfLoops(true).build();
    undirectedGraph.putEdgeValue(N1, N1, E11);
    undirectedGraph.putEdgeValue(N1, N2, E12);
    undirectedGraph.putEdgeValue(N2, N1, E21); // overwrites E12

    return undirectedGraph;
  }

  private static MutableNetwork<Integer, String> buildDirectedNetwork() {
    MutableNetwork<Integer, String> directedGraph =

          putRangeMapEntry(
              rangeToRemove.upperBound,
              rangeMapEntry.getUpperBound(),
              mapEntryBelowToTruncate.getValue().getValue());
        }
        // overwrite mapEntryToTruncateBelow with a truncated range
        putRangeMapEntry(
            rangeMapEntry.getLowerBound(),
            rangeToRemove.lowerBound,
            mapEntryBelowToTruncate.getValue().getValue());

        ImmutableList<AbstractFuture<T>> delegates, int inputFutureIndex) {
      /*
       * requireNonNull is safe because we accepted an Iterable of non-null Future instances, and we
       * don't overwrite an element in the array until after reading it.
       */
      ListenableFuture<? extends T> inputFuture = requireNonNull(inputFutures[inputFutureIndex]);
      // Null out our reference to this future, so it can be GCed

                  </fileset>
                </copy>
                <!-- Any manually written supersource should take priority over the original guava source, so we set overwrite=true. -->
                <copy toDir="${project.build.directory}/guava-gwt-sources" overwrite="true">
                  <fileset dir="src-super" />
                </copy>
                <copy toDir="${project.build.directory}/guava-test-gwt-sources">

  }

  @Test
  public void undirectedGraph() {
    graph = ValueGraphBuilder.undirected().allowsSelfLoops(true).build();
    graph.putEdgeValue(1, 2, "valueA");
    graph.putEdgeValue(2, 1, "valueB"); // overwrites valueA in undirected case
    graph.putEdgeValue(2, 3, "valueC");
    graph.putEdgeValue(4, 4, "valueD");

    assertThat(graph.edgeValueOrDefault(1, 2, null)).isEqualTo("valueB");

        ValueGraphBuilder.undirected().allowsSelfLoops(true).build();
    undirectedGraph.putEdgeValue(N1, N1, E11);
    undirectedGraph.putEdgeValue(N1, N2, E12);
    undirectedGraph.putEdgeValue(N2, N1, E21); // overwrites E12

    return undirectedGraph;
  }

  private static MutableNetwork<Integer, String> buildDirectedNetwork() {
    MutableNetwork<Integer, String> directedGraph =