public virtual void xmlLexiconImmutabilityTest()
{
NLGFactory factory = new NLGFactory(lexicon);
Realiser realiser = new Realiser(lexicon);
// "wall" is singular.
NPPhraseSpec wall = factory.createNounPhrase("the", "wall");
Assert.AreEqual(NumberAgreement.SINGULAR, wall.getFeature(Feature.NUMBER));
// Realise a sentence with plural form of "wall"
wall.Plural = true;
SPhraseSpec sentence = factory.createClause("motion", "observe");
sentence.setFeature(Feature.TENSE, Tense.PAST);
PPPhraseSpec pp = factory.createPrepositionPhrase("in", wall);
sentence.addPostModifier(pp);
realiser.realiseSentence(sentence);
// Create a new 'the wall' NP and check to make sure that the syntax processor has
// not propagated plurality to the canonical XMLLexicon WordElement object.
wall = factory.createNounPhrase("the", "wall");
Assert.AreEqual(NumberAgreement.SINGULAR, wall.getFeature(Feature.NUMBER));
}