* whose next element can always be derived from the previous element. Null elements are not
 * supported, nor is the {@link #remove()} method.
 *
 * <p>Example:
 *
 * {@snippet :
 * Iterator<Integer> powersOfTwo =
 *     new AbstractSequentialIterator<Integer>(1) {
 *       protected Integer computeNext(Integer previous) {
 *         return (previous == 1 << 30) ? null : previous * 2;
 *       }
 *     };
 * }
 *

     *
     * @return The global toolchains source or {@code null} if none.
     */
    Source getGlobalToolchainsSource();

    /**
     * Sets the global toolchains source. If both user toolchains and a global toolchains are given, the user toolchains
     * take precedence.
     *
     * @param globalToolchainsSource The global toolchains source, may be {@code null} to disable global toolchains.

    /**
     * Gets the source from which the model was read.
     *
     * @return The source from which the model was read, never {@code null}.
     */
    @Nonnull
    ModelSource getSource();

    /**
     * Gets the file model.
     *
     * @return the file model, never {@code null}.
     */
    @Nonnull
    Model getFileModel();

    /**

        verify(messageBlock).getDigest();
    }

    @Test
    @DisplayName("Test setDigest with null value")
    void testSetDigestWithNull() {
        // Given
        doNothing().when(messageBlock).setDigest(null);
        when(messageBlock.getDigest()).thenReturn(null);

        // When
        messageBlock.setDigest(null);
        SMBSigningDigest retrievedDigest = messageBlock.getDigest();

        // Then

        String msg, pathInfo, server = null;
        boolean offerBasic, possibleWorkgroup = true;
        NtlmPasswordAuthentication ntlm = null;
        final HttpSession ssn = req.getSession(false);

        pathInfo = req.getPathInfo();
        if (pathInfo != null) {
            int i;
            server = parseServerAndShare(pathInfo);
            if (server != null && (i = server.indexOf('/')) > 0) {

        assertNotNull(exception);
        assertNull(exception.getCause());
        assertNull(exception.getMessage());
    }

    @Test
    public void test_constructor_withNullMessageAndCause() {
        // Test with both null message and cause
        DataStoreException exception = new DataStoreException(null, null);

        assertNotNull(exception);
        assertNull(exception.getMessage());

        JobProcess jobProcess = new JobProcess(mockProcess, 0, null);

        assertNotNull(jobProcess.getInputStreamThread());
    }

    @Test
    public void test_constructor_withNullCallback() throws IOException {
        Process mockProcess = createMockProcess("test");
        JobProcess jobProcess = new JobProcess(mockProcess, 10, null);

        assertNotNull(jobProcess.getInputStreamThread());
    }

    }

    @Test
    @DisplayName("readParameterWordsWireFormat with null buffer - throws NullPointerException")
    void testReadParameterWordsWithNullBuffer() {
        assertThrows(NullPointerException.class, () -> response.readParameterWordsWireFormat(null, 0));
    }

    @Test
    @DisplayName("readParameterWordsWireFormat with offset beyond buffer - throws exception")

            eventCatapult.fire(ExecutionEvent.Type.SessionEnded, session, null);
        }
    }

    public List<TaskSegment> calculateTaskSegments(MavenSession session) throws Exception {

        MavenProject rootProject = session.getTopLevelProject();

        List<String> tasks = requireNonNull(session.getGoals()); // session never returns null, but empty list

        if (tasks.isEmpty()

    GraphConnections<N, V> connectionsV = nodeConnections.get(nodeV);
    if (connectionsU == null || connectionsV == null) {
      return null;
    }

    V previousValue = connectionsU.removeSuccessor(nodeV);
    if (previousValue != null) {
      connectionsV.removePredecessor(nodeU);
      checkNonNegative(--edgeCount);
    }
    return previousValue;
  }