}
    }

    /**
     * Test multiple concurrent search operations.
     * Verifies that parallel searches don't interfere with each other.
     */
    @Test
    public void test_multipleConcurrentSearches() throws Exception {
        final int numSearchThreads = 5;
        final CountDownLatch startLatch = new CountDownLatch(1);
        final CountDownLatch endLatch = new CountDownLatch(numSearchThreads);