Mock Metadata Usage in a GetStreamingChatMessageContentsAsync response

[romainsemur]

Hi,

In this article about unit test (https://devblogs.microsoft.com/semantic-kernel/unit-testing-with-semantic-kernel/) , in the DoWorkWithPrompt() method, how to add a metadata with Usage values in the returns ?
.Returns(new List() { new(AuthorRole.Assistant, "AI response") }.ToAsyncEnumerable());

[sophialagerkranspandey]

Tagging @dmytrostruk

[dmytrostruk]

Hi @romainsemur ,
Here is an updated example with metadata including Usage in return:

[Fact]
public async Task DoWorkWithPrompt()
{
    // Arrange 
    var mockChatCompletion = new Mock<IChatCompletionService>();

    var mockResponse = new ChatMessageContent(
            AuthorRole.Assistant,
            "AI response",
            metadata: new Dictionary<string, object?>
            {
                { "Usage",
                    new Dictionary<string, int>
                    {
                        { "InputTokenCount", 18 },
                        { "OutputTokenCount", 242 },
                        { "TotalTokenCount", 260 }
                    }
                }
            });

    mockChatCompletion
        .Setup(x => x.GetChatMessageContentsAsync(
            It.IsAny<ChatHistory>(),
            It.IsAny<PromptExecutionSettings>(),
            It.IsAny<Kernel>(),
            It.IsAny<CancellationToken>()))
        .ReturnsAsync([mockResponse]);

    var kernelBuilder = Kernel.CreateBuilder();
    kernelBuilder.Services.AddSingleton(mockChatCompletion.Object);

    var kernel = kernelBuilder.Build();
    var service = new MyService(kernel);

    // Act 
    var result = await service.DoWorkAsync("Prompt to AI");

    // Assert 
    Assert.Equal("AI response", result.ToString());

    if (result.Metadata is not null &&
        result.Metadata.TryGetValue("Usage", out var metadataObj) &&
        metadataObj is Dictionary<string, int> metadata)
    {
        Assert.Equal(18, metadata["InputTokenCount"]);
        Assert.Equal(242, metadata["OutputTokenCount"]);
        Assert.Equal(260, metadata["TotalTokenCount"]);
    }
}

Please let us know if that works for you, thanks!