CODEWITHSUNDEEP
c#azureunit-testingmockingmoq
user10816949
user10816949

Reputation: 171

How can I implement mock(s) for this unit test?

I need to write a unit test for the following method:

private async Task<bool> CreateFileAsync(string fileContent, string containerName, string fileName, string connectionString)
{
  CloudStorageAccount cloudStorageAccount = await GetCloudStorageAccount(connectionString);
  CloudBlobClient blobClient = cloudStorageAccount.CreateCloudBlobClient();
  CloudBlobContainer containerRef = blobClient.GetContainerReference(containerName);
  CloudBlockBlob blobRef = containerRef.GetBlockBlobReference(fileName);
  await blobRef.UploadTextAsync(fileContent);

  return true;
}

I need to write an xUnit unit test which will throw an HttpException when blobRef.UploadTextAsync(fileContent) is called.

Microsoft.WindowsAzure.Storage.CloudBlockBlob : Microsoft.WindowsAzure.Storage.Blob.ICloudBlob

But CloudStorageAccount doesn't implement an interface so it does not appear that I can mock it.

Here's some sample unit test code based on what I understand about mocking and pieced together for this particular scenario:

var cloudBlockBlobMock = new Mock<ICloudBlob>();
cloudBlockBlobMock
    .Setup(cbb => cbb.UploadTextAsync("test"))
    .Throws<HttpException>();
var fileUploader = new FileUploader(cloudBlockBlobMock);
fileUploader.CreateFileAsync("test");

Is CreateFileAsync() unit-testable?

Is it possible/valid to mock a child object without mocking its parent object?

Upvotes: 1

Views: 6414

Answers (2)

N Krishnia
N Krishnia

Reputation: 315

Maybe you can use the below code snippet

Mock<CloudStorageAccount> obj = new Mock<CloudStorageAccount>();

and then you can setup any function or property

Upvotes: 0

Peter Bons
Peter Bons

Reputation: 29720

Microsoft took another approach when it came to making the libs unit testable. Instead of implementing interfaces, the types have most methods virtual. For example, the CloudStorageAccount.CreateCloudBlobClient method is virtual. You can mock those in Moq.

Or you could use a wrapper that wraps the implementation in an interface and use that. See e.g. Microsoft/Azure.Data.Wrappers or pvredeveld/Azure.Storage.Wrappers. These will provide an interface you can mock but you have to change your existing codebase to use them.

Upvotes: 5

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