// // Thread may still be alive in test environment
        // assertFalse(indexUpdater.isAlive());
    }

    // Test updateDocument with boost matcher
    public void test_updateDocument_withBoostMatcher() {
        final Map<String, Object> doc = new HashMap<>();
        doc.put("url", "http://example.com");

        final DocBoostMatcher matcher = new DocBoostMatcher() {
            @Override