}

  /**
   * Appends the string representation of each of {@code parts}, using the previously configured
   * separator between each, to {@code builder}. Identical to {@link #appendTo(Appendable,
   * Iterable)}, except that it does not throw {@link IOException}.
   */
  @CanIgnoreReturnValue
  public final StringBuilder appendTo(

    assertEquals("a", Strings.commonPrefix("abc", "aaaaa"));
    assertEquals("aa", Strings.commonPrefix("aa", "aaaaa"));
    assertEquals("abc", Strings.commonPrefix(new StringBuffer("abcdef"), "abcxyz"));

    // Identical valid surrogate pairs.
    assertEquals(
        "abc\uD8AB\uDCAB", Strings.commonPrefix("abc\uD8AB\uDCABdef", "abc\uD8AB\uDCABxyz"));
    // Differing valid surrogate pairs.

import java.io.DataInput;
import java.io.IOException;
import javax.annotation.CheckForNull;

/**
 * An extension of {@code DataInput} for reading from in-memory byte arrays; its methods offer
 * identical functionality but do not throw {@link IOException}.
 *
 * <p><b>Warning:</b> The caller is responsible for not attempting to read past the end of the

public class AbstractNonStreamingHashFunctionTest extends TestCase {
  /**
   * Constructs two trivial HashFunctions (output := input), one streaming and one non-streaming,
   * and checks that their results are identical, no matter which newHasher version we used.
   */
  public void testExhaustive() {
    List<Hasher> hashers =
        ImmutableList.of(
            new StreamingVersion().newHasher(),

public class AbstractNonStreamingHashFunctionTest extends TestCase {
  /**
   * Constructs two trivial HashFunctions (output := input), one streaming and one non-streaming,
   * and checks that their results are identical, no matter which newHasher version we used.
   */
  public void testExhaustive() {
    List<Hasher> hashers =
        ImmutableList.of(
            new StreamingVersion().newHasher(),

   */
  public static <N> Graph<N> transpose(Graph<N> graph) {
    if (!graph.isDirected()) {
      return graph; // the transpose of an undirected graph is an identical graph
    }

    if (graph instanceof TransposedGraph) {
      return ((TransposedGraph<N>) graph).graph;
    }

    return new TransposedGraph<>(graph);
  }

  /**

      throws Throwable;

  /**
   * By default delegates to {@link Object#equals} so instances are only equal if they are
   * identical. {@code proxy.equals(argument)} returns true if:
   *
   * <ul>
   *   <li>{@code proxy} and {@code argument} are of the same type
   *   <li>and this method returns true for the {@link InvocationHandler} of {@code argument}

    Object[] array = collection.toArray();
    expectArrayContentsAnyOrder(createSamplesArray(), array);
  }

  /**
   * {@link Collection#toArray(Object[])} says: "Note that {@code toArray(new Object[0])} is
   * identical in function to {@code toArray()}."
   *
   * <p>For maximum effect, the collection under test should be created from an element array of a
   * type other than {@code Object[]}.
   */

    Object[] array = collection.toArray();
    expectArrayContentsAnyOrder(createSamplesArray(), array);
  }

  /**
   * {@link Collection#toArray(Object[])} says: "Note that {@code toArray(new Object[0])} is
   * identical in function to {@code toArray()}."
   *
   * <p>For maximum effect, the collection under test should be created from an element array of a
   * type other than {@code Object[]}.
   */

   * 'affect' a bit(j) in the output if two inputs, identical but for bit(i), will differ at output
   * bit(j) about half the time
   *
   * <p>Funneling is pretty simple to detect. The key idea is to find example keys which
   * unequivocally demonstrate that funneling cannot be occurring. This is done bit-by-bit. For each
   * input bit(i) and output bit(j), two pairs of keys must be found with all bits identical except