public void combines_the_list_of_all_errors() { var graph = new FixtureStructure("Math"); graph.AddStructure("key1", new StubGrammarStructure().AddError("error1")); graph.AddStructure("key2", new StubGrammarStructure().AddError("error1").AddError("error 2")); graph.AllErrors().Count().ShouldEqual(3); }