// Test with different types of causes
        DataStoreException withIOException = new DataStoreException("IO Error", new java.io.IOException("File not found"));
        DataStoreException withNPE = new DataStoreException("NPE Error", new NullPointerException("Null value"));
        DataStoreException withCustom = new DataStoreException("Custom Error", new FessSystemException("System error"));

        dataMap.put("title", "Test Document");

        // Execute and verify exception
        try {
            indexUpdateCallback.store(paramMap, dataMap);
            fail("Should throw DataStoreException");
        } catch (DataStoreException e) {
            assertTrue(e.getMessage().contains("url is null"));
        }
    }

    public void test_store_withLabels() {
        // Setup label matching