public void WithAServiceCollection_ThenATokenServiceIsAdded()
        {
            Mock <IServiceCollection> services = new Mock <IServiceCollection>();

            ExtensionsHelper.AddTokenService(services.Object);

            services.Verify(instance => instance.Add(It.Is <ServiceDescriptor>(x =>
                                                                               x.Lifetime == ServiceLifetime.Scoped &&
                                                                               x.ServiceType == typeof(ITokenService) &&
                                                                               x.ImplementationType == typeof(TokenService))), Times.Once);
        }
        public void WithoutAServiceCollection_ThenAnExceptionIsThrown()
        {
            ArgumentNullException exception = Assert.Throws <ArgumentNullException>(() => ExtensionsHelper.AddTokenService(null));

            Assert.AreEqual("services", exception.ParamName);
        }