public async Task SubscriptionRegistrationPostReturnsOk()
        {
            // Arrange
            var function = new SubscriptionRegistrationHttpTrigger(logger, environmentValues, subscriptionRegistrationService);

            // Act
            var result = await function.Run(null).ConfigureAwait(false);

            // Assert
            A.CallTo(() => subscriptionRegistrationService.RegisterSubscription(A <string> .Ignored)).MustHaveHappenedOnceExactly();
            Assert.IsType <OkResult>(result);
        }
        public async Task SubscriptionRegistrationPostThrowsException()
        {
            // Arrange
            A.CallTo(() => subscriptionRegistrationService.RegisterSubscription(A <string> .Ignored)).ThrowsAsync(new HttpRequestException());
            var function = new SubscriptionRegistrationHttpTrigger(logger, environmentValues, subscriptionRegistrationService);

            // Act
            var result = await function.Run(null).ConfigureAwait(false);

            // Assert
            A.CallTo(() => subscriptionRegistrationService.RegisterSubscription(A <string> .Ignored)).MustHaveHappenedOnceExactly();
            Assert.IsType <InternalServerErrorResult>(result);
        }