@Test
    public void test_defaultField() {
        queryContext = new QueryContext("test", false);
        assertNull(queryContext.getDefaultField());

        queryContext.setDefaultField("custom_field");
        assertEquals("custom_field", queryContext.getDefaultField());

        queryContext.setDefaultField(null);
        assertNull(queryContext.getDefaultField());
    }

        field.setAccessible(true);
        @SuppressWarnings("unchecked")
        final java.util.Set<String> standardFields = (java.util.Set<String>) field.get(null);

        assertFalse(standardFields.contains("custom_field"));
        assertFalse(standardFields.contains("department"));
        assertFalse(standardFields.contains("author"));
    }

    // ===================================================================================