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

    @Test
    public void test_constructor_withEmptyMessage() {
        // Test with empty message
        String message = "";
        LdapConfigurationException exception = new LdapConfigurationException(message);

        assertNotNull(exception);
        assertEquals(message, exception.getMessage());

        assertEquals(message, exception.getMessage());
        assertEquals(cause, exception.getCause());
    }

    @Test
    public void test_constructorWithNullMessage() {
        // Test constructor with null message
        StorageException exception = new StorageException(null);

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

        assertTrue(exception instanceof RuntimeException);
        assertTrue(exception instanceof Exception);
        assertTrue(exception instanceof Throwable);
    }

    @Test
    public void test_serializable() {
        // Test that the exception has serialVersionUID
        WebApiException exception = new WebApiException(404, "Not Found");

        String message1 = "First exception";
        String message2 = "Second exception";

        UnsupportedSearchException exception1 = new UnsupportedSearchException(message1);
        UnsupportedSearchException exception2 = new UnsupportedSearchException(message2);

        assertNotSame(exception1, exception2);
        assertEquals(message1, exception1.getMessage());

        Exception exception = new Exception("Test failure");
        result.addFailure(exception);

        assertTrue(result.hasFailure());
        assertEquals(1, result.getFailures().size());
        assertEquals(exception, result.getFailures().get(0));
    }

    @Test
    public void test_addMultipleFailures() throws Exception {
        SuggestWriterResult result = new SuggestWriterResult();

        FessUserNotFoundException exception1 = new FessUserNotFoundException("user1");
        FessUserNotFoundException exception2 = new FessUserNotFoundException("user2");

        assertNotSame(exception1, exception2);
        assertFalse(exception1.getMessage().equals(exception2.getMessage()));
        assertEquals("User is not found: user1", exception1.getMessage());

        assertTrue(exception instanceof FessSystemException);
        assertTrue(exception instanceof RuntimeException);
        assertTrue(exception instanceof Exception);
        assertTrue(exception instanceof Throwable);

        // Should be runtime exception (unchecked), not an Error
        // CommandExecutionException extends RuntimeException, not Error

        // Test that different instances are not equal
        DictionaryExpiredException exception1 = new DictionaryExpiredException();
        DictionaryExpiredException exception2 = new DictionaryExpiredException();

        assertNotSame(exception1, exception2);
        assertFalse(exception1.equals(exception2));
        assertTrue(exception1.equals(exception1));
    }

    @Test
    public void test_hashCode() {

        assertTrue(exception.getMessage().contains(cause.getClass().getName()));
        assertTrue(exception.getMessage().contains("Cause exception"));
    }

    @Test
    public void test_constructor_withNullMessage() {
        // Test constructor with null message
        FessSystemException exception = new FessSystemException((String) null);

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

        assertThat(toSqlDateJdbcEscape(null), is(nullValue()));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testToSqlDate_EmptyString() throws Exception {
        assertThat(toSqlDateJdbcEscape(""), is(nullValue()));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testToSqlDate_ShortStyle() throws Exception {