public void ReturnsNullAtRecursionPoint() { // Fixture setup var builder = new DelegatingSpecimenBuilder(); builder.OnCreate = (r, c) => c.Resolve(r); var sut = new NullRecursionGuard(builder); var container = new DelegatingSpecimenContext(); container.OnResolve = r => sut.Create(r, container); // Provoke recursion // Exercise system object res = sut.Create(Guid.NewGuid(), container); Assert.Null(res); }