public void SingleRegistrationServiceTypes_AreNotRegistered_MultipleTimes() { // Arrange var services = new ServiceCollection(); var multiRegistrationServiceTypes = MutliRegistrationServiceTypes; // Act MvcServiceCollectionExtensions.AddMvcServices(services); MvcServiceCollectionExtensions.AddMvcServices(services); // Assert var singleRegistrationServiceTypes = services .Where(serviceDescriptor => !multiRegistrationServiceTypes.Contains(serviceDescriptor.ServiceType)) .Select(serviceDescriptor => serviceDescriptor.ServiceType); foreach (var singleRegistrationType in singleRegistrationServiceTypes) { AssertServiceCountEquals(services, singleRegistrationType, 1); } }