C# - Verify a method is called or not in Unit Test

C# - Verify a method is called or not in Unit Test

C# Unit testing Moq

I have a unit test I am checking whether a method is called once or not so I attempted this way:-

This is my Mock of ILicenseManagerService and I am passing its object through constructor.

    public Mock<ILicenseManagerService> LicenseManagerService { get { return SetLicenseManagerServiceMock(); } }

        private Mock<ILicenseManagerService> SetLicenseManagerServiceMock()
            var licencemangerservicemock = new Mock<ILicenseManagerService>();
            licencemangerservicemock.Setup(m => m.LoadProductLicenses()).Returns(ListOfProductLicense).Verifiable();

            return licencemangerservicemock;

        public static async Task<IEnumerable<IProductLicense>> ListOfProductLicense()
            var datetimeoffset = new DateTimeOffset(DateTime.Now);

            var lst = new List<IProductLicense>
                GetProductLicense(true, datetimeoffset, false, "1"),
                GetProductLicense(true, datetimeoffset, false, "2"),
                GetProductLicense(true, datetimeoffset, true, "3")

            return lst;

I am using this mock object to set _licenseManagerService and calling the LoadProductLicenses() in method under test. like this. licences are coming fine.

var licenses = (await _licenseManagerService.LoadProductLicenses()).ToList();

My attempt for verify the call to this method -

 LicenseManagerService.Verify(m => m.LoadProductLicenses(),Times.Once);

But when I run my unit test, an exception coming that say method is not invoked at all. Where I am doing wrong ?

EDIT I am invoking the same mock here is my unit test.

        public async Task return_products_from_web_when_cache_is_empty()
            // this class basically for setting up external dependencies
            // Like - LicenceManagerService in context, i am using this mock only no new mock.
            var inAppMock = new InAppMock ();                  

            // object of Class under test- I used static method for passing external         
            //services for easy to change 
            var inAppStore = StaticMethods.GetInAppStore(inAppMock);

            // method is called in this method
            var result = await inAppStore.LoadProductsFromCacheOrWeb();

            // like you can see using the same inAppMock object and same LicenseManagerService
            inAppMock.LicenseManagerService.Verify(m => m.LoadProductLicenses(),Times.Once);   


LicenseManagerService.Verify(m => m.LoadProductLicenses(),Times.Once);

By calling the LicenseManagerService property, you're creating a new mock object. Naturally, no invocations have ever been performed on this instance.

You should change this property's implementation to return the same instance every time it is called.


StackOverflow - https://stackoverflow.com/questions/24402945/verify-a-method-is-called-or-not-in-unit-test

Archive - https://archive.ph/XcMVw

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