public void TestParsing14() {
var g = new Grammar(new List<Production>{
CFGParser.Production("<S> → ε"),
CFGParser.Production("<S> → <A> 'x'"),
CFGParser.Production("<A> → <S>"),
}, Nonterminal.Of("S"));
var sentences = new List<Sentence>();
sentences.Add(Sentence.FromWords("x"));
ExecuteTest(g, sentences);
}