Microsoft.DurableTask.InProcessTestHost 0.2.3-preview.1

DurableTaskTestHost - Testing Durable Orchestrations In-Process

DurableTaskTestHost is a simple API for testing your durable task orchestrations and activities in-process without requiring any external backend.

Supports both class-based and function-based syntax.

Quick Start

1. Configure options (optional)

var options = new DurableTaskTestHostOptions
{
 Port = 31000, // Optional: specific port (random by default)
 LoggerFactory = myLoggerFactory // Optional: pass logger factory for logging
};

2. Register test orchestrations and activities

await using var testHost = await DurableTaskTestHost.StartAsync(registry =>
{
 // Class-based
 registry.AddOrchestrator<MyOrchestrator>();
 registry.AddActivity<MyActivity>();
 
 // Function-based
 registry.AddOrchestratorFunc("MyFunc", (ctx, input) => Task.FromResult("done"));
 registry.AddActivityFunc("MyActivity", (ctx, input) => Task.FromResult("result"));
});

3. Test

string instanceId = await testHost.Client.ScheduleNewOrchestrationInstanceAsync("MyOrchestrator");
var result = await testHost.Client.WaitForInstanceCompletionAsync(instanceId);

Dependency Injection

When your activities depend on services, there are two approaches:

Option 1: ConfigureServices

Use this when you want the test host to manage everything. Register services directly in the test host options.

await using var host = await DurableTaskTestHost.StartAsync(
 tasks =>
 {
 tasks.AddOrchestrator<MyOrchestrator>();
 tasks.AddActivity<MyActivity>();
 },
 new DurableTaskTestHostOptions
 {
 ConfigureServices = services =>
 {
 // Register services required by your orchestrator or activity function
 services.AddSingleton<IMyService, MyService>();
 services.AddSingleton<IUserRepository, InMemoryUserRepository>();
 services.AddLogging();
 }
 });

var instanceId = await host.Client.ScheduleNewOrchestrationInstanceAsync(nameof(MyOrchestrator), "input");
var result = await host.Client.WaitForInstanceCompletionAsync(instanceId, getInputsAndOutputs: true);

Access registered services via host.Services:

var myService = host.Services.GetRequiredService<IMyService>();

Option 2: AddInMemoryDurableTask

Use this when you already have a host with complex DI setup (database, auth, external APIs, etc.) and want to add durable task testing to it.

public class MyIntegrationTests : IAsyncLifetime
{
 IHost host = null!;
 DurableTaskClient client = null!;

 public async Task InitializeAsync()
 {
 this.host = Host.CreateDefaultBuilder()
 .ConfigureServices(services =>
 {
 // Your existing services (from Program.cs, Startup.cs, etc.)
 services.AddSingleton<IUserRepository, InMemoryUserRepository>();
 services.AddScoped<IOrderService, OrderService>();
 services.AddDbContext<MyDbContext>();

 // Add in-memory durable task support
 services.AddInMemoryDurableTask(tasks =>
 {
 tasks.AddOrchestrator<MyOrchestrator>();
 tasks.AddActivity<MyActivity>();
 });
 })
 .Build();

 await this.host.StartAsync();
 this.client = this.host.Services.GetRequiredService<DurableTaskClient>();
 }
}

Access the in-memory orchestration service:

var orchestrationService = host.Services.GetInMemoryOrchestrationService();

API Reference

DurableTaskTestHostOptions

DurableTaskTestHost

Extension Methods

More Samples

See , , and for complete samples.