@Nullable Object get() throws Throwable;
  }

  @CanIgnoreReturnValue
  static <T extends Throwable> T assertThrows(
      Class<T> expectedThrowable, ThrowingSupplier supplier) {
    return doAssertThrows(expectedThrowable, supplier, /* userPassedSupplier= */ true);
  }

  @CanIgnoreReturnValue
  static <T extends Throwable> T assertThrows(
      Class<T> expectedThrowable, ThrowingRunnable runnable) {

    assertThat(Optional.of("a").or(Suppliers.ofInstance("fallback"))).isEqualTo("a");
  }

  public void testOr_supplier_absent() {
    assertEquals("fallback", Optional.absent().or(Suppliers.ofInstance("fallback")));
  }

  public void testOr_nullSupplier_absent() {
    Supplier<Object> nullSupplier = (Supplier<Object>) Suppliers.<@Nullable Object>ofInstance(null);

  }

  @Override
  public Optional<T> or(Optional<? extends T> secondChoice) {
    checkNotNull(secondChoice);
    return this;
  }

  @Override
  public T or(Supplier<? extends T> supplier) {
    checkNotNull(supplier);
    return reference;
  }

  @Override
  public T orNull() {
    return reference;
  }

  @Override
  public Set<T> asSet() {
    return Collections.singleton(reference);

     *
     * @param user the user object with new attribute values
     * @param adminEnv the supplier for admin environment
     * @param userDN the DN of the user entry
     * @param result the search results containing current attributes
     */
    protected void modifyUserAttributes(final User user, final Supplier<Hashtable<String, String>> adminEnv, final String userDN,
            final List<SearchResult> result) {

  }

  private static void assertChecksum(ImmutableSupplier<Checksum> supplier, String input) {
    byte[] bytes = HashTestUtils.ascii(input);

    Checksum checksum = supplier.get();
    checksum.update(bytes, 0, bytes.length);
    long value = checksum.getValue();

    String toString = "name";
    HashFunction func = new ChecksumHashFunction(supplier, 32, toString);
    assertThat(func.toString()).isEqualTo(toString);

    static Stream<Arguments> implementations() {
        return Stream.of(Arguments.of("returns self", (Supplier<SmbRenewableCredentials>) SelfRenewingCreds::new, true, false),
                Arguments.of("returns new", (Supplier<SmbRenewableCredentials>) NewRenewingCreds::new, false, true),
                Arguments.of("returns null", (Supplier<SmbRenewableCredentials>) NullRenewingCreds::new, false, false));
    }

      Supplier<T> supplier) {
    return new SupplierFunction<>(supplier);
  }

  /**
   * @see Functions#forSupplier
   */
  private static final class SupplierFunction<
          F extends @Nullable Object, T extends @Nullable Object>
      implements Function<F, T>, Serializable {

    private final Supplier<T> supplier;

    private SupplierFunction(Supplier<T> supplier) {

    @Nullable Object get() throws Throwable;
  }

  @CanIgnoreReturnValue
  static <T extends Throwable> T assertThrows(
      Class<T> expectedThrowable, ThrowingSupplier supplier) {
    return doAssertThrows(expectedThrowable, supplier, /* userPassedSupplier= */ true);
  }

  @CanIgnoreReturnValue
  static <T extends Throwable> T assertThrows(
      Class<T> expectedThrowable, ThrowingRunnable runnable) {

    @Nullable Object get() throws Throwable;
  }

  @CanIgnoreReturnValue
  static <T extends Throwable> T assertThrows(
      Class<T> expectedThrowable, ThrowingSupplier supplier) {
    return doAssertThrows(expectedThrowable, supplier, /* userPassedSupplier= */ true);
  }

  @CanIgnoreReturnValue
  static <T extends Throwable> T assertThrows(
      Class<T> expectedThrowable, ThrowingRunnable runnable) {

                this.beanEntry = beanEntry;
                return this;
            }

            @Override
            public Supplier<T> compile(Function<Dependency<?>, Supplier<?>> compiler) {
                return beanEntry.getProvider()::get;
            }
        }

        class BridgeProvider<T> implements Provider<T> {
            final Binding<T> binding;