public static TestContext.Result A <T>(this TestContext.Result @this,
                                               Action <T> mutator) where T : class
        {
            var @obj = TestFixture.Value.Create <T>();

            mutator(@obj);
            return(@this.State.Register(services => services.AddTransient(_ => @obj)));
        }
 public static TestContext.Result An <T>(this TestContext.Result @this, Action <T> mutator) where T : class => A(@this, mutator);
 public static TestContext.Result An <T>(this TestContext.Result @this) where T : class => A <T>(@this);