C# : How to unit test Graph SDK Batch Request

Even though writing unit tests for Azure Graph SDK became easier, writing unit test for Batch request was little bit confusing to me.

Source Code

This is my class which I want to write unit test. I omit some business logic on purpose, this is not simple wrapper in real project.

• DI GraphServiceClient
• Return User objects via Batch Request
• Use AddBatchRequestStep to control requestId

public class GraphService
{
    private readonly GraphServiceClient graphServiceClient;

    public GraphService(GraphServiceClient graphServiceClient)
    {
        this.graphServiceClient = graphServiceClient;
    }

    public async Task<List<User>> GetUsersAsync(List<string> userIds)
    {
        List<User> users = new();
        BatchRequestContent batchRequestContent = new();
        userIds.ForEach(x =>
        {
            batchRequestContent.AddBatchRequestStep(new BatchRequestStep(x, graphServiceClient.Users[x]
                    .Request().Select(u => new
                    {
                        u.Id,
                        u.GivenName,
                        u.Mail,
                        u.Surname,
                        u.UserPrincipalName
                    }).GetHttpRequestMessage()));
        });

        BatchResponseContent returnedResponse = await graphServiceClient.Batch.Request().PostAsync(batchRequestContent);
        userIds.ForEach(async x =>
        {
            User user = await returnedResponse.GetResponseByIdAsync<Microsoft.Graph.User>(x);
            users.Add(user);
        });

        return users;
    }
}

Unit Test Code

I don't know if there is better way to achieve the same, but this is what I did by following advice in GitHub issue

• Create response as json string
• Mock IHttpProvider to handle SendAsync request. Return the json string as StringContent
• Mock GraphServiceClient ahd pass mocked IHttpProvider as constructor
• Mock GetHttpRequestMessage method as this is called in AddBatchRequestStep

[Fact]
public async Task ReturnsUsers()
{
    // Arrenge
    string userId = "dummy_id1";
    string userId2 = "dummy_id2";
    string batchResponse = @$"{{
""responses"":[{{
    ""id"": ""{userId}"",
    ""status"":200,
    ""headers"":
    {{
        ""Content-Type"":""application/json""
    }},
    ""body"":
    {{
        ""@odata.context"":""https://graph.microsoft.com/v1.0/$metadata#users/$entity"",
        ""surName"":""Test"",
        ""givenName"":""User1"",
        ""id"":""{userId}""
    }}
  }},
{{
    ""id"": ""{userId2}"",
    ""status"":200,
    ""headers"":
    {{
        ""Content-Type"":""application/json""
    }},
    ""body"":
    {{
        ""@odata.context"":""https://graph.microsoft.com/v1.0/$metadata#users/$entity"",
        ""surName"":""Test"",
        ""givenName"":""User2"",
        ""id"":""{userId2}""
    }}
  }}]
}}";
    Mock<IHttpProvider> mockedIHttpProvider = new();
    mockedIHttpProvider.Setup(x => x.SendAsync(
        It.IsAny<HttpRequestMessage>(), 
        It.IsAny<HttpCompletionOption>(), 
        It.IsAny<CancellationToken>()))
        .ReturnsAsync(new HttpResponseMessage()
        {
            StatusCode = HttpStatusCode.OK,
            Content = new StringContent(batchResponse),
        });
    Mock<IAuthenticationProvider> mockedIAuthenticationProvider = new();
    Mock<GraphServiceClient> mockedGraphServiceClient = new(
        mockedIAuthenticationProvider.Object, mockedIHttpProvider.Object);
    mockedGraphServiceClient.Setup(x => x.Users[It.IsAny<string>()]
        .Request()
        .Select(It.IsAny<Expression<Func<Microsoft.Graph.User, object>>>()).GetHttpRequestMessage())
        .Returns(new HttpRequestMessage() { RequestUri = new Uri("http://localhost/v1.0/users") });
    GraphService graphService = new(mockedGraphServiceClient.Object);

    // Act
    List<User> users = await graphService.GetUsersAsync(new List<string>() { userId, userId2 }).ConfigureAwait(false);

    // Assert
    Assert.True(users.Count == 2);
}

Summary

There are several trips required so I wish I can find better/easier way to achieve it in the future.

Of course we can mock any behavior and objects. Simply change request and response.