}
    }

    /**
     * Test that Set lookup behavior is identical to original array-based lookup.
     * This ensures backward compatibility.
     */
    @Test
    public void test_isSortField_behaviourIdenticalToArrayLookup() {
        String[] fields = { "score", "created", "modified" };
        queryFieldConfig.setSortFields(fields);

        // Test positive cases
        for (String field : fields) {