public void AddAllowRule_Works()
        {
            var configBuilder = new AnalyzerConfigBuilder()
                                .AddAllowRule(new NamespaceDependencyRule("N1", "N2"))
                                .AddAllowRule(new NamespaceDependencyRule("N3", "N4"), new TypeNameSet {
                "T1", "T2"
            });

            configBuilder
            .AddAllowRule(new NamespaceDependencyRule("N3", "N4"), new TypeNameSet {
                "T2", "T3"
            })
            .AddAllowRule(new NamespaceDependencyRule("N5", "N6"), new TypeNameSet {
                "T4"
            });

            configBuilder.AllowRules.ShouldBeEquivalentTo(
                new Dictionary <NamespaceDependencyRule, TypeNameSet>
            {
                { new NamespaceDependencyRule("N1", "N2"), null },
                { new NamespaceDependencyRule("N3", "N4"), new TypeNameSet {
                      "T1", "T2", "T3"
                  } },
                { new NamespaceDependencyRule("N5", "N6"), new TypeNameSet {
                      "T4"
                  } },
            });
        }