.NET 1.0.1 Unit test strategy

[jimmy-vo-librestream]

I am working on upgrading 1.0.0-beta8 to 1.0.1, and I found it is not possible to mock Kenel, Function, or Pluggin. For example I have an extension function that my business logic calling to:

    public static async Task<string> InvokePromptAsync(
        this Kernel kernel,
        KernelArguments variables,
        string template,
        OpenAIPromptExecutionSettings requestSettings,
        CancellationToken cancellationToken = default)
    {
        KernelFunction skFunction = kernel.CreateFunctionFromPrompt(template, requestSettings);
        var result = await kernel.InvokeAsync<string>(skFunction, variables, cancellationToken);
        return result!;
    }

In 1.0.0-beta8, I was able to mock ISKFunction, IReadOnlyFunctionCollection, and IKernel. But they are removed in 1.0.1. KernelFunction is now an abstract class with internal constructor, so there is no way I can create a MockKernelFunction that wraps KernelFunction and overrides ValueTask<FunctionResult> InvokeCoreAsync(Kernel kernel, KernelArguments arguments, CancellationToken cancellationToken).

I am currious how you guys do it?

[pratibw]

Does anyone know how to setup the mock for InvokeAsync?

this.kernelMock.Setup(k => k.InvokeAsync(It.IsAny(), It.IsAny())).ReturnsAsync(It.IsAny());

this is throwing an error and I am not able to mock the call.

[matthewbolanos]

Per @markwallace-microsoft guidance on #4589, you can take a look at our existing unit tests here for KernelFunction:

KernelFunctionFromMethodTests1.cs
KernelFunctionFromMethodTests2.cs
KernelFunctionFromPromptTests.cs

For your use case you can mock the AI service and add that to the Kernel you use in your unit tests. We're going to take a look at providing guidance around unit testing.

[dmytrostruk]

@jimmy-vo-librestream @pratibw Here is a blog post about unit testing of Semantic Kernel components:
https://devblogs.microsoft.com/semantic-kernel/unit-testing-with-semantic-kernel/

Hope it will help!