List<String> testValue = null;
        OptionalEntity<List<String>> result = OptionalUtil.ofNullable(testValue);

        assertNotNull(result);
        assertFalse(result.isPresent());
    }

    @Test
    public void test_ofNullable_withMap() {
        Map<String, Object> testValue = new HashMap<>();
        testValue.put("key1", "value1");
        testValue.put("key2", 42);

                    "https://search.domain.com:443" };

            for (String testValue : testValues) {
                System.setProperty(Constants.FESS_SEARCH_ENGINE_HTTP_ADDRESS, testValue);
                String result = SystemUtil.getSearchEngineHttpAddress();
                assertEquals(testValue, result);
            }
        } finally {
            // Restore original value

        try {
            WebApiUtil.setObject("testKey", "testValue");
        } catch (Exception e) {
            fail("setObject should handle missing request gracefully: " + e.getMessage());
        }
    }

    @Test
    public void test_setObject_withNullName() {
        // Test setObject with null name
        try {
            WebApiUtil.setObject(null, "testValue");
        } catch (Exception e) {

    @Test
    public void test_inheritedMethods_areProperlyDelegated() {
        final String customPath = "/api/v1/test";
        final String testHeader = "X-Test-Header";
        final String testHeaderValue = "TestValue";

        mockRequest.addHeader(testHeader, testHeaderValue);
        mockRequest.setMethod("POST");
        mockRequest.setRequestURI("/test/uri");

        }
    }

    // Test sendMail method
    @Test
    public void test_sendMail_withNotificationDisabled() {
        Map<String, String> infoMap = new HashMap<>();
        infoMap.put("TestKey", "TestValue");

        // Should not throw exception when notification is disabled
        try {
            crawler.sendMail(infoMap);
        } catch (Exception e) {