UnitTestEx.Azure.Functions.Durable 7.0.0-preview

UnitTestEx.Azure.Functions.Durable (preview)

Optional 7.0.0-preview package for fluent in-memory Durable Task SDK-host tests, activity mocks, invocation verification, managed diagnostics and a separate method-level virtual-time context. Regular UnitTestEx dependencies use 7.0.0.

Preview and scope: This evolving implementation targets key testing scenarios, not exhaustive Durable Functions coverage. It depends on Microsoft's preview Microsoft.DurableTask.InProcessTestHost 0.2.3-preview.1; breaking changes may occur between preview releases. Request additional scenarios.

Quick start

using System;
using System.Threading.Tasks;
using UnitTestEx;
using UnitTestEx.Azure.Functions.Durable.TestHost;

using var functions = FunctionTester.Create<WorkflowActivities>();
await using var run = await functions.DurableTask()
    .Orchestrator<string, string>("OutputProbe", (_, input) => Task.FromResult(input))
    .StartAsync("hello");
await run.WaitForCompletionAsync(TimeSpan.FromSeconds(10),
    result => result.AssertCompleted().AssertOutput("hello"));

Use an ordinary class from your Functions application assembly in place of WorkflowActivities. This minimal delegate checks wiring; register delegates to real application orchestrations/activities to test their behavior. The showcase runs a real batch body with controlled activity responses.

To run application activities and orchestrations without forwarding delegates, use functions.DurableTask().WithSelfDiscovery(). It scans only the parent marker's assembly; WithSelfDiscovery<T>() adds another marker's assembly. Explicit registrations override discoveries. Direct orchestration runs select a root with .Orchestrator(...); for a starter function, use .StartHostAsync(), pass session.Client explicitly, and observe its known instance ID with session.Observe<TOutput>(id). See the starter example. Dispose the run before the session and FunctionTester. Real instance activities use owned invocation scopes; discovered instance orchestrations retain separate scopes across replay until session/run disposal. Duplicate names/unsupported signatures fail early. Real activities may have external side effects.

Boundaries

• SDK-host orchestration timers and retry delays use wall-clock time, not virtual time.
• VirtualTimeOrchestrationContext is a separate method-level timer/event tool without engine history/replay or activity/child execution.
• The pinned SDK host has a buffered-event preservation limitation across ContinueAsNew; use real-worker integration to test preservation.
• SDK-host tests do not run the Functions worker or prove binding/serializer parity. Ordinary activity-method tests use FunctionTester.Trigger<T>() without this optional package.
• Starter tests invoke the method directly with an SDK-host client; they do not exercise Service Bus delivery or [DurableClient] binding.

AI assistance and documentation

The package includes skills/unittestex-durable/SKILL.md, version-matched to these APIs and boundaries. See discovery and optional installation.

• Durable guide and support matrix
• Architecture
• Real Functions integration