assertFalse(future.isCancelled());
  }

  public void testSetValue_simpleThreaded() throws Exception {
    SettableFuture<Integer> future = SettableFuture.create();
    assertTrue(future.set(42));
    // Later attempts to set the future should return false.
    assertFalse(future.set(23));
    assertFalse(future.setException(new Exception("bar")));
    assertFalse(future.setFuture(SettableFuture.<Integer>create()));

    assertFalse(future.isCancelled());
  }

  public void testSetValue_simpleThreaded() throws Exception {
    SettableFuture<Integer> future = SettableFuture.create();
    assertTrue(future.set(42));
    // Later attempts to set the future should return false.
    assertFalse(future.set(23));
    assertFalse(future.setException(new Exception("bar")));
    assertFalse(future.setFuture(SettableFuture.<Integer>create()));

    assertEquals(Optional.of("a"), Optional.of("a").transform(Functions.identity()));
  }

  public void testTransform_presentToString() {
    assertEquals(Optional.of("42"), Optional.of(42).transform(Functions.toStringFunction()));
  }

  public void testTransform_present_functionReturnsNull() {
    try {
      Optional<String> unused =
          Optional.of("a")
              .transform(

    byte[] dest = new byte[4];
    HashCode.fromInt(42).writeBytesTo(dest, 0, 4);
    assertTrue(Arrays.equals(HashCode.fromInt(42).asBytes(), dest));
  }

  public void testLongWriteBytesTo() {
    byte[] dest = new byte[8];
    HashCode.fromLong(42).writeBytesTo(dest, 0, 8);
    assertTrue(Arrays.equals(HashCode.fromLong(42).asBytes(), dest));
  }

  private static final HashCode HASH_ABCD =

    Interner<String> pool = Interners.newStrongInterner();
    assertThrows(NullPointerException.class, () -> pool.intern(null));
  }

  public void testStrong_builder() {
    int concurrencyLevel = 42;
    Interner<Object> interner =
        Interners.newBuilder().strong().concurrencyLevel(concurrencyLevel).build();
    InternerImpl<Object> internerImpl = (InternerImpl<Object>) interner;

 *
 * @author Kurt Alfred Kluever
 */
public class HashCodeBenchmark {

  // Use a statically configured random instance for all of the benchmarks
  private static final Random random = new Random(42);

  @Param({"1000", "100000"})
  private int size;

  @Param WhereToDiffer whereToDiffer;

  @Param EqualsImplementation equalsImpl;

  private enum WhereToDiffer {
    ONE_PERCENT_IN,
    LAST_BYTE,

    CacheStats one = new CacheStats(11, 13, 17, 19, 23, 27);
    CacheStats two = new CacheStats(53, 47, 43, 41, 37, 31);

    CacheStats diff = two.minus(one);
    assertEquals(76, diff.requestCount());
    assertEquals(42, diff.hitCount());
    assertEquals(42.0 / 76, diff.hitRate());
    assertEquals(34, diff.missCount());
    assertEquals(34.0 / 76, diff.missRate());
    assertEquals(26, diff.loadSuccessCount());

 *
 * @author Kurt Alfred Kluever
 */
public class HashCodeBenchmark {

  // Use a statically configured random instance for all of the benchmarks
  private static final Random random = new Random(42);

  @Param({"1000", "100000"})
  private int size;

  @Param WhereToDiffer whereToDiffer;

  @Param EqualsImplementation equalsImpl;

  private enum WhereToDiffer {
    ONE_PERCENT_IN,
    LAST_BYTE,

  }

  @Test
  public void undirectedGraph() {
    testGraphMutation(GraphBuilder.undirected());
  }

  private static void testGraphMutation(GraphBuilder<? super Integer> graphBuilder) {
    Random gen = new Random(42); // Fixed seed so test results are deterministic.

    for (int trial = 0; trial < NUM_TRIALS; ++trial) {
      MutableGraph<Integer> graph = graphBuilder.allowsSelfLoops(true).build();

      return;
    }
    out.write(data);
    assertTrue(Arrays.equals(data, source.read()));

    out.close();
    assertThrows(IOException.class, () -> out.write(42));

    // Verify that write had no effect
    assertTrue(Arrays.equals(data, source.read()));
    out.reset();
  }

  public void testReset() throws Exception {
    byte[] data = newPreFilledByteArray(100);