*/
    @Nonnull
    Optional<Source> getSource();

    /**
     * Determines whether a stub model should be allowed when the POM is missing or unreadable.
     * A stub model contains only minimal information derived from the project's coordinates.
     *
     * @return true if a stub model should be allowed, false otherwise
     */
    boolean isAllowStubModel();

    /**

        }
    }

    /**
     * Derives an AES key using the Kerberos key derivation function.
     * This method implements the simplified key derivation for AES encryption types.
     *
     * @param key the base Kerberos key
     * @param constant the key derivation constant
     * @return the derived key bytes
     * @throws GeneralSecurityException if cryptographic operations fail

     * Gets the identifier of the model from which the problem originated. While the general form of this identifier is
     * <code>groupId:artifactId:version</code> the returned identifier need not be complete. The identifier is derived
     * from the information that is available at the point the problem occurs and as such merely serves as a best effort
     * to provide information to the user to track the problem back to its origin.
     *

    NavigableSet<E> empty = navigableSet.subSet(e0(), false, e0(), false);
    assertEquals(new TreeSet<E>(), empty);
  }

  /*
   * TODO(cpovirk): more testing of subSet/headSet/tailSet/descendingSet? and/or generate derived
   * suites?
   */

  /**
   * Returns the {@link Method} instances for the test methods in this class that create a set with

          parentBuilder) {
    // TODO: Once invariant support is added, supply invariants to each of the
    // derived suites, to check that mutations to the derived collections are
    // reflected in the underlying map.

    List<TestSuite> derivedSuites = super.createDerivedSuites(parentBuilder);

    AsyncFunction<Throwable, Integer> fallback = unused -> secondary;
    ListenableFuture<Integer> derived =
        catchingAsync(primary, Throwable.class, fallback, directExecutor());
    secondary.set(1);
    assertEquals(1, (int) getDone(derived));
  }

  public void testCatchingAsync_resultInterruptedBeforeFallback() throws Exception {

    AsyncFunction<Throwable, Integer> fallback = unused -> secondary;
    ListenableFuture<Integer> derived =
        catchingAsync(primary, Throwable.class, fallback, directExecutor());
    secondary.set(1);
    assertEquals(1, (int) getDone(derived));
  }

  public void testCatchingAsync_resultInterruptedBeforeFallback() throws Exception {

    E duplicate = elements[(elements.length / 2) - 1];
    elements[(elements.length / 2) + 1] = duplicate;
    return new ArrayWithDuplicate<>(elements, duplicate);
  }

  // Helper methods to improve readability of derived classes

  protected int getNumElements() {
    return getSubjectGenerator().getCollectionSize().getNumElements();
  }

  protected Collection<E> getSampleElements(int howMany) {

 *
 * @param <B> The concrete type of this builder (the 'self-type'). All the Builder methods of this
 *     class (such as {@link #named}) return this type, so that Builder methods of more derived
 *     classes can be chained onto them without casting.
 * @param <G> The type of the generator to be passed to testers in the generated test suite. An

        .suppressing(parentBuilder.getSuppressedTests())
        .createTestSuite();
  }

  /**
   * To avoid infinite recursion, test suites with these marker features won't have derived suites
   * created for them.
   */
  enum NoRecurse implements Feature<Void> {
    SUBMULTISET,
    DESCENDING;

    @Override
    public Set<Feature<? super Void>> getImpliedFeatures() {