source.put("TestKey", "value1");
        source.put("AnotherTestKey", "value2");

        Map<String, Object> nested = new HashMap<>();
        nested.put("NestedKey", "nestedValue");
        source.put("NestedMap", nested);

        Map<String, Object> result = searchLogHelper.toLowerHyphen(source);

        assertEquals("value1", result.get("test_key"));

    @Test
    public void test_append_nullValue() {
        StringBuilder buf = new StringBuilder();
        Supplier<Object> supplier = () -> null;

        monitorTarget.append(buf, "testKey", supplier);
        assertEquals("\"testKey\":null", buf.toString());
    }

    // Test append method with Integer value
    @Test
    public void test_append_integerValue() {
        StringBuilder buf = new StringBuilder();

        }
    }

    // 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) {