Map<String, Object> map = new HashMap<>();
        map.put("key", "value");

        assertEquals("value", MapValueExtractor.getString(map, "key"));
    }

    @Test
    public void testGetString_withNullValue() {
        Map<String, Object> map = new HashMap<>();
        map.put("key", null);

        assertNull(MapValueExtractor.getString(map, "key"));
    }

    @Test