How to mock or unit test AzureStorageAccount with xunit

Question

Hi, 

Want to unit test below code:


CloudStorageAccount storageAccount = CloudStorageAccount.Parse("connString");
CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
CloudBlobContainer container = blobClient.GetContainerReference("containerName");
CloudBlockBlob cloudBlobInstance = container.GetBlockBlobReference(container, "imageName");
cloudBlobInstance.UploadFromByteArrayAsync(ImageBytes, 0, ImageByt

and to do this I move below code to a wrapper like:

public class AzureServiceWrapper : IAzureServiceWrapper
    {
        public CloudStorageAccount GetCloudStorageAccount(string connString)
        {
            CloudStorageAccount cloudStorageAccountClient = CloudStorageAccount.Parse(connString);
            return cloudStorageAccountClient;
        }
        public CloudBlockBlob GetBlockBlobReference(CloudBlobContainer storageContainer, string fileName)
        {
            return storageContainer.GetBlockBlobReference(fileName);
        }
          public CloudBlobClient GetBlobClient(CloudStorageAccount cloudStorageAccountClient)
        {      
            CloudBlobClient cloudBlobClient = cloudStorageAccountClient.CreateCloudBlobClient();
            return cloudBlobClient;
        }    

         public CloudBlobContainer GetBlobContainer(CloudBlobClient cloudBlobClient, string containerName)
        {     CloudBlobContainer cloudBlobContainer = cloudBlobClient.GetContainerReference(containerName);
            return cloudBlobContainer;
        }
    }
}

And then using this interface I can Inject it and modify my repo code like:

CloudStorageAccount cloudStorageAccountClient = _azureSeriveWrapper.GetStorageAccount("connString"); 
CloudBlobClient cloudBlobClient  = _azureSeriveWrapper.GetBlobClient(cloudStorageAccountClient); 
CloudBlobContainer cloudBlobContainer= _azureSeriveWrapper.GetBlobContainer(cloudBlobClient,"containerName");
 CloudBlockBlob cloudBlobInstance = _azureSeriveWrapper.GetBlockBlobReference(cloudBlobContainer, AssetImageName); 
 cloudBlobInstance.UploadFromByteArrayAsync(ImageBytes, 0, ImageBytes.Length); 
 mediaUrl = cloudBlobInstance.Uri.AbsoluteUri;

But how to mock this in unit test method if above is correct or please help me with the sample code for the same.

Thanks in advance,

Answer 1

you need a wrapper for all the Storage objects (CloudStorageAccount, CloudBlockBlob, etc) that your wrapper returns.

a better approach is to abstract all the methods you will use to return poco objects.

mocking generally depends on interface design or class inheritance. so a mock of IAzureServiceWrapper would return mock objects. for example GetCloudStorageAccount would return a mock CloudStorageAccount(). if you write the mocks yourself you the mock class inherits from CloudStorageAccount and would implements all the methods called by test.

TDD usually requires designs the objects to be easily testable.