public void TestCNFNoNull01() {
var productions = new HashSet<Production> {
CFGParser.Production("<A> -> <A> <B>"),
CFGParser.Production("<A> -> <B>"),
CFGParser.Production("<A> -> 'a'"),
CFGParser.Production("<B> -> <A>"),
CFGParser.Production("<B> -> 'b'"),
};
Grammar g = new Grammar(productions, Nonterminal.Of("A"));
CNFGrammar h = g.ToCNF();
Helpers.AssertNear(0, h.Cyk(Sentence.FromLetters("")));
Helpers.AssertNear(0.4, h.Cyk(Sentence.FromLetters("a")));
Helpers.AssertNear(0.2, h.Cyk(Sentence.FromLetters("b")));
Helpers.AssertNear(0.096, h.Cyk(Sentence.FromLetters("ab")));
Helpers.AssertNear(0.048, h.Cyk(Sentence.FromLetters("bb")));
Helpers.AssertNear(0.032, h.Cyk(Sentence.FromLetters("aa")));
Helpers.AssertNear(0.016, h.Cyk(Sentence.FromLetters("ba")));
}