assertNotNull(result);
        assertEquals(thumbnailFile.getAbsolutePath(), result.getAbsolutePath());
    }

    // Test getThumbnailFile with non-existing file
    @Test
    public void test_getThumbnailFile_notExists() {
        Map<String, Object> docMap = new HashMap<>();
        docMap.put("_id", "nonexistent");

        File result = thumbnailManager.getThumbnailFile(docMap);
        assertNull(result);
    }