    @Test
    public void testCreateNominal() throws Exception {

        assertEquals("Nominal values were not set properly", nominal_values, field.getCategoricalInstances());
        assertEquals("Instance name not set properly", name, field.getName());

        int index = 0;
        for(String v : nominal_values) {
            assertEquals("Known value must be unchanged", index, (int) field.parseOrMissing(v));
            index++;
        }
    }