// Test with concrete implementation - behavior depends on implementation
            // May throw NullPointerException
            try {
                concreteImplementation.append(null);
            } catch (NullPointerException e) {
                // Expected for some implementations
            }
        }
    }

    @Nested

        }

        @Test
        @DisplayName("createResponse throws NullPointerException when CIFSContext is null")
        void createResponse_nullContext_throws() {
            // Arrange
            Smb2LogoffRequest req = newRequest();

            // Act/Assert
            assertThrows(NullPointerException.class, () -> req.createResponse(null, req));
        }

        @Test

          .put(IndexOutOfBoundsException.class, e -> e instanceof IndexOutOfBoundsException)
          .put(NoSuchElementException.class, e -> e instanceof NoSuchElementException)
          .put(NullPointerException.class, e -> e instanceof NullPointerException)
          .put(NumberFormatException.class, e -> e instanceof NumberFormatException)
          .put(RuntimeException.class, e -> e instanceof RuntimeException)

            Exception rootCause = new NullPointerException();
            TransportException exception = new TransportException(rootCause);

            String result = exception.toString();

            assertNotNull(result);
            assertTrue(result.contains("TransportException"));
            assertTrue(result.contains("NullPointerException"));
            assertTrue(result.contains("\n"));
        }

        assertTrue(exception1.getCause() instanceof java.io.IOException);

        StorageException exception2 = new StorageException("NPE", new NullPointerException("Null reference"));
        assertTrue(exception2.getCause() instanceof NullPointerException);

        StorageException exception3 = new StorageException("Custom", new FessSystemException("System error"));

    Map<Class<? extends Number>, Number> nullKey = singletonMap(null, (Number) 1.0);
    assertThrows(NullPointerException.class, () -> ImmutableClassToInstanceMap.copyOf(nullKey));

    Map<? extends Class<? extends Number>, Number> nullValue = singletonMap(Number.class, null);
    assertThrows(NullPointerException.class, () -> ImmutableClassToInstanceMap.copyOf(nullValue));
  }

  public void testCopyOf_imap_empty() {

    expectContents(createArrayWithNullKey());
  }

  @MapFeature.Require(absent = ALLOWS_NULL_KEYS)
  @CollectionSize.Require(absent = ZERO)
  public void testCreateWithNullKeyUnsupported() {
    assertThrows(NullPointerException.class, () -> initMapWithNullKey());
  }

  @MapFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testCreateWithNullValueSupported() {
    initMapWithNullValue();

    this.type = type;
    this.allowNulls = allowNulls;

    if (!allowNulls) {
      for (Object element : contents) {
        if (element == null) {
          throw new NullPointerException();
        }
      }
    }
  }

  @Override
  public int size() {
    return contents.length;
  }

  @Override
  public boolean contains(@Nullable Object object) {
    if (!allowNulls) {

            assertTrue(ex.getMessage().contains("Bad textual SID format"));
        }

        @Test
        @DisplayName("Textual constructor null throws NullPointerException")
        void testTextualConstructorNull() {
            assertThrows(NullPointerException.class, () -> new SID((String) null));
        }

        @Test
        @DisplayName("Binary constructor happy path and round-trip via toByteArray")

    assertThat(Strings.padStart("x", -1, '-')).isSameInstanceAs("x");
  }

  @SuppressWarnings("nullness") // test of a bogus call
  public void testPadStart_null() {
    assertThrows(NullPointerException.class, () -> Strings.padStart(null, 5, '0'));
  }

  public void testPadEnd_noPadding() {
    assertThat(Strings.padEnd("", 0, '-')).isSameInstanceAs("");