verify(true);
  }

  public void testVerify_simple_failure() {
    try {
      verify(false);
      fail();
    } catch (VerifyException expected) {
    }
  }

  public void testVerify_simpleMessage_success() {
    verify(true, "message");
  }

  public void testVerify_simpleMessage_failure() {
    try {
      verify(false, "message");
      fail();

    @Nullable private String value = null;
    @Nullable private Throwable failure = null;
    private boolean wasCalled = false;

    MockCallback(String expectedValue) {
      this.value = expectedValue;
    }

    public MockCallback(Throwable expectedFailure) {
      this.failure = expectedFailure;
    }

    @Override
    public synchronized void onSuccess(String result) {

   * reading, such as an {@code InputStream}. Unlike with writable resources, there's no chance that
   * a failure that occurs when closing the stream indicates a meaningful problem such as a failure
   * to flush all bytes to the underlying resource.
   *
   * @param inputStream the input stream to be closed, or {@code null} in which case this method
   *     does nothing

 *     Guava 27.0
 */
public final class InternalFutures {
  /**
   * Usually returns {@code null} but, if the given {@code Future} has failed, may <i>optionally</i>
   * return the cause of the failure. "Failure" means specifically "completed with an exception"; it
   * does not include "was cancelled." To be explicit: If this method returns a non-null value,
   * then:
   *
   * <ul>

    assertTrue(future.setException(new Exception("failure")));
    tester.testFailedFuture("failure");
  }

  public void testSetFailureNull() throws Exception {
    assertThrows(NullPointerException.class, () -> future.setException(null));
    assertFalse(future.isDone());
    assertTrue(future.setException(new Exception("failure")));
    tester.testFailedFuture("failure");
  }

  public void testCancel() throws Exception {

    assertTrue(future.setException(new Exception("failure")));
    tester.testFailedFuture("failure");
  }

  public void testSetFailureNull() throws Exception {
    assertThrows(NullPointerException.class, () -> future.setException(null));
    assertFalse(future.isDone());
    assertTrue(future.setException(new Exception("failure")));
    tester.testFailedFuture("failure");
  }

  public void testCancel() throws Exception {

  }

  public void testCheckNoOverflow_failure() {
    try {
      MathPreconditions.checkNoOverflow(false, "testCheckNoOverflow_failure", 0, 0);
      fail();
    } catch (ArithmeticException expected) {
      assertThat(expected).hasMessageThat().contains("testCheckNoOverflow_failure(0, 0)");
    }
  }

  public void testNulls() {
    /*

    assertEquals(100, file.length());
    assertTrue(file.exists());
    out.close();

    // Make sure that finalize deletes the file
    out = null;

    // times out and throws RuntimeException on failure
    GcFinalization.awaitDone(
        new GcFinalization.FinalizationPredicate() {
          @Override
          public boolean isDone() {
            return !file.exists();
          }
        });
  }

   * the call to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
   *
   * @param message message to use upon assertion failure
   */
  protected void expectNullKeyMissingWhenNullKeysUnsupported(String message) {
    try {
      assertFalse(message, getMap().containsKey(null));
    } catch (NullPointerException tolerated) {

   * to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
   *
   * @param message message to use upon assertion failure
   */
  protected void expectNullMissingWhenNullUnsupported(String message) {
    try {
      assertFalse(message, actualContents().contains(null));
    } catch (NullPointerException tolerated) {
      // Tolerated