assertNotNull(updated);
        assertTrue(updated.containsKey(FieldNames.DOC_FREQ));
        assertTrue(updated.containsKey(FieldNames.QUERY_FREQ));
    }

    @Test
    public void testSourceContainsExpectedFields() {
        String[] text = { "test" };
        String[][] readings = { { "reading" } };
        String[] fields = { "field" };