checkArgument(
          !(connectionsU != null && connectionsU.successors().contains(nodeV)),
          PARALLEL_EDGES_NOT_ALLOWED,
          nodeU,
          nodeV);
    }
    boolean isSelfLoop = nodeU.equals(nodeV);
    if (!allowsSelfLoops()) {
      checkArgument(!isSelfLoop, SELF_LOOPS_NOT_ALLOWED, nodeU);
    }

    if (connectionsU == null) {
      connectionsU = addNodeInternal(nodeU);
    }

        Long expiration = 123456789L;
        when(mockResponse.getExpiration()).thenReturn(expiration);
        assertEquals(expiration, mockResponse.getExpiration());

        // Test null expiration
        when(mockResponse.getExpiration()).thenReturn(null);
        assertNull(mockResponse.getExpiration());

        // Verify the method was called
        verify(mockResponse, times(2)).getExpiration();
    }

    @Test

     * is too restrictive or permissive for your use case.
     * </p>
     *
     * @param bytes the byte array (must not be {@literal null})
     * @param filter the ObjectInputFilter to use, or null to disable filtering
     * @return the deserialized object
     * @throws IORuntimeException if an I/O error occurs or if a class is rejected by the filter

             * based on the configured remote repos.
             */
            MavenSession session = legacySupport.getSession();
            if (session != null) {
                MavenExecutionRequest req = session.getRequest();
                if (req != null) {
                    request.setActiveProfileIds(req.getActiveProfiles());
                    request.setInactiveProfileIds(req.getInactiveProfiles());
                }

        assertSame(messages, result);
        assertTrue(messages.hasMessageOf(property));
    }

    // Test null property handling
    @Test
    public void test_addErrorsFrontHeader_nullProperty() {
        try {
            messages.addErrorsFrontHeader(null);
            fail("Should throw exception for null property");
        } catch (IllegalArgumentException e) {
            // Expected
        }
    }

     * @return A set of matched label values.
     */
    public Set<String> getMatchedLabelValueSet(final String path) {
        if (labelTypePatternList == null) {
            synchronized (this) {
                if (labelTypePatternList == null) {
                    buildLabelTypePatternList(ComponentUtil.getComponent(LabelTypeService.class).getLabelTypeList());
                }
            }
        }

        File f = new File(getBasedir(), path);

        f.createNewFile();

        return artifactRepositoryFactory.createArtifactRepository(
                "test", "file://" + f.getPath(), repoLayout, null, null);
    }

    protected String getRepositoryLayout() {
        return "default";
    }

    protected ArtifactRepository localRepository() throws Exception {

    initMultimapWithNullKey();

    assertContentsAnyOrder(multimap().removeAll(null), getValueForNullKey());

    expectMissing(mapEntry((K) null, getValueForNullKey()));
  }

  @MapFeature.Require({SUPPORTS_REMOVE, ALLOWS_ANY_NULL_QUERIES})
  public void testRemoveAllNullKeyAbsent() {
    assertEmpty(multimap().removeAll(null));
    expectUnchanged();
  }

      @Override
      protected @Nullable Integer computeNext(Integer previous) {
        return (previous == last) ? null : previous * 2;
      }
    };
  }

  private static class EmptyAbstractSequentialIterator<T> extends AbstractSequentialIterator<T> {

    EmptyAbstractSequentialIterator() {
      super(null);
    }

    @Override
    protected T computeNext(T previous) {
      throw new AssertionFailedError();

    /**
     * Returns an {@link Iterable} that wraps an {@link IndexedIterator} for use in a for-each statement.
     *
     * @param <T> the element type
     * @param iterable the iterable (must not be {@literal null})
     * @return an {@link Iterable} wrapping an {@link IndexedIterator}
     */
    public static <T> Iterable<Indexed<T>> indexed(final Iterable<T> iterable) {
        assertArgumentNotNull("iterable", iterable);