assertEquals(200, response.getStatusCode());
        String body = response.getBody().asString();
        assertTrue(body != null && body.length() > 0, "Response body should not be empty");
        // NDJSON format: each line is a JSON object
        String[] lines = body.trim().split("\n");
        assertTrue(lines.length > 0, "Should have at least one line in NDJSON response");
    }

    @Test

                            } else {
                                boolean empty = callback.deleteUrlList.isEmpty();
                                // Just verify the check doesn't throw exception
                                if (!empty) {
                                    assertTrue(callback.deleteUrlList.size() > 0);
                                }

    }

    @Override
    public void delete(final User user) {
        final String username = user.getName();
        if (isTargetUser(username)) {
            executeCommand(deleteCommand, username, StringUtil.EMPTY);
        }
    }

    @Override
    public boolean changePassword(final String username, final String password) {
        if (isTargetUser(username) && StringUtil.isNotBlank(password)) {

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

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

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

        for (final SynonymItem synonymItem : synonymItemList) {
            if (id == synonymItem.getId()) {
                return OptionalEntity.of(synonymItem);
            }
        }
        return OptionalEntity.empty();
    }

    @Override
    public synchronized PagingList<SynonymItem> selectList(final int offset, final int size) {
        if (synonymItemList == null) {
            reload(null);
        }

        return new FessConfig.SimpleImpl() {
            private static final long serialVersionUID = 1L;

            @Override
            public String get(String key) {
                // Override to return empty string instead of null to avoid NullPointerException
                return "";
            }

            @Override
            public String getIndexFieldTitle() {
                return "title";
            }

        }

        List<String> cmdList = mockProcessHelper.getLastCommandList();
        assertNotNull(cmdList, "Command list should not be null");
        assertTrue("Command list should not be empty", !cmdList.isEmpty());

        int cpIndex = cmdList.indexOf("-cp");
        assertTrue("Should have -cp argument", cpIndex >= 0);
        if (cpIndex >= 0 && cpIndex + 1 < cmdList.size()) {

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

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

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

        assertEquals(statusCode, exception.getStatusCode());
        assertEquals(message, exception.getMessage());
    }

    @Test
    public void test_message_emptyString() {
        // Test with empty message string
        int statusCode = 404;
        String message = "";

        WebApiException exception = new WebApiException(statusCode, message);

        assertEquals(statusCode, exception.getStatusCode());

        assertEquals("Executed: type null", result);

        result = jobExecutor.execute(null, null);
        assertEquals("Executed: null null", result);

        // Test with empty strings
        result = jobExecutor.execute("", "");
        assertEquals("Executed:  ", result);
    }

    @Test
    public void test_addShutdownListener() {
        // Test adding shutdown listener