How to mock SearchClient.SearchAsync with the Azure Cognitive Search SDK?

Question

I am trying to unit test code that uses SearchClient.SearchAsync() method. I am using AutoFixture.AutoMoq nuget package.

Here is what I tried:

mockSearchClient.Setup(msc => msc.SearchAsync<MyModel>(
        It.IsAny<string>(),
        It.IsAny<SearchOptions>(),
        It.IsAny<CancellationToken>()
    )).Returns(Task.FromResult(<<PROBLEM HERE>>));

The problem lies in the parameter .Returns(Task.FromResult(<<PROBLEM HERE>>)) part. It expects a concrete object that is returned from the .SearchAsync() method. According to docs and autocomplete, the method returns Azure.Response which is an abstract class. So, I cannot new it up. In actuality, the method returns a descendant class Azure.ValueResponse, which isn't abstract, but is internal to Azure SDK, so also impossible to new up.

So how does one mock the SearchClient.SearchAsync?

P.S. Using Azure.Search.Documents, v11.1.1.0

Answer 1

See https://github.com/Azure/azure-sdk-for-net/blob/master/sdk/core/Azure.Core/README.md#mocking for information. Basically, you can use Response.FromValue along with the SearchModelFactory (a pattern we follow with all our Azure.* client SDKs for models that can't be fully mocked with a constructor and/or settable properties) to create a mock like so (using Moq, since I'm unfamiliar with AutoMoq, but should be similar):

var responseMock = new Mock<Response>();

var clientMock = new Mock<SearchClient>(() => new SearchClient(new Uri("https://localhost"), "index", new AzureKeyCredential("key")));
clientMock.SetupGet(x => x.IndexName).Returns("index");
clientMock.Setup(x => x.SearchAsync<Hotel>(
        It.IsAny<string>(),
        It.IsAny<SearchOptions>(),
        It.IsAny<CancellationToken>()
    ))
    .Returns(
        Task.FromResult(
            Response.FromValue(
                SearchModelFactory.SearchResults(new[]
                    {
                        SearchModelFactory.SearchResult(new Hotel("1", "One"), 0.9, null),
                        SearchModelFactory.SearchResult(new Hotel("2", "Two"), 0.8, null),
                    },
                    100,
                    null,
                    null,
                    responseMock.Object),
                responseMock.Object)));

var results = await clientMock.Object.SearchAsync<Hotel>("test").ConfigureAwait(false);
var hotels = results.Value;

Assert.Equal(2, hotels.GetResults().Count());
Assert.Equal(100, hotels.TotalCount);