Shinsuke Sugaya <******@****.***> 1768400947 +0900

            // If it doesn't throw NPE, it should provide an empty stream
            assertEquals(0, stream.count());
        });
    }

    @Test
    public void test_init_withInvalidDefaultFields() {
        // Test with invalid default field formats
        FessConfig fessConfig = new FessConfig.SimpleImpl() {

            @Override
            public String getQueryAdditionalDefaultFields() {