Adds Amazon.Lambda.DurableExecution.Testing

[GarrettBeatty]

Summary

Adds Amazon.Lambda.DurableExecution.Testing — a NuGet package for testing durable workflows.

Write your test once against IDurableTestRunner<TInput, TOutput> and run it either:

• locally (DurableTestRunner) — in-process on the real runtime engine with an in-memory backend (fast, no AWS), or
• against a deployed function (CloudDurableTestRunner) — invokes the real Lambda and polls for the result.

Both return the same TestResult<TOutput> for assertions (status, result, error, and per-step inspection via GetStep/GetResult<T>).

Supports time-skipping, the callback flow, and sibling-function registration. Adds an internal IDurableServiceClient seam to the runtime package (no public API change).

Example

using Amazon.Lambda.DurableExecution.Testing;
using Xunit;

public class OrderWorkflowTests
{
    [Fact]
    public async Task MultiStepWorkflow_Succeeds()
    {
        await using var runner = new DurableTestRunner<int, int>(
            handler: async (input, ctx) =>
            {
                var doubled = await ctx.StepAsync(async (_, _) => input * 2, name: "double");
                return await ctx.StepAsync(async (_, _) => doubled + 10, name: "add_ten");
            });

        var result = await runner.RunAsync(5);

        result.EnsureSucceeded();
        Assert.Equal(20, result.Result);

        // Inspect individual steps
        var step = result.GetStep("double");
        Assert.Equal(OperationStatus.Succeeded, step.Status);
        Assert.Equal(10, step.GetResult<int>());
    }
}

The same assertions run unchanged against a deployed function by swapping the runner:

await using var runner = new CloudDurableTestRunner<int, int>(
    functionArn: "arn:aws:lambda:us-east-1:123456789012:function:order-processor:live");

var result = await runner.RunAsync(5);
result.EnsureSucceeded();

Day-long WaitAsync / callback workflows complete in milliseconds locally (time-skipping is on by default), and ctx.InvokeAsync siblings resolve in-process via RegisterFunction / RegisterDurableFunction. See the package README for the callback and sibling-invoke patterns.

Test plan

• 106 unit tests passing on net8.0 and net10.0
• Portable scenarios verified end-to-end against real deployed functions
• Existing runtime tests unaffected

[GarrettBeatty]

moved all of these common workflows to a different re-usable file so that the local and cloud runner tests can also re-use the existing integ tests

[GarrettBeatty]

closing this to separate it into two prs to make release easier