public void TestToCNF06() {
Grammar g = new Grammar(new List<Production>{
CFGParser.Production("<S> → ε"),
CFGParser.Production("<S> → 'x' <A>")
}, Nonterminal.Of("S"));
CNFGrammar h = g.ToCNF();
Helpers.AssertNear(1.0, h.Cyk(Sentence.FromWords("")));
}