AzureFunctions.TestFramework.Durable 0.11.1

AzureFunctions.TestFramework.Durable

Fake-backed Durable Functions test helpers for the Azure Functions Test Framework. Includes ConfigureFakeDurableSupport(...), FakeDurableTaskClient, direct activity invocation, fake orchestration scheduling, sub-orchestrators, external events, and HTTP status polling helpers.

No real Durable Task runtime or external storage (Azure Storage / Netherite / MSSQL) is needed.

Why fake-backed?

The real Durable Task execution engine relies on external storage and the Durable Task Framework host, neither of which runs inside the test framework's in-process worker. ConfigureFakeDurableSupport(...) registers a FakeDurableTaskClient and companion types that intercept [DurableClient] binding resolution at the DI level, letting starter functions, orchestrators, activities, and sub-orchestrators execute fully in-process.

Setup

using AzureFunctions.TestFramework.Core;
using AzureFunctions.TestFramework.Durable;

_testHost = await new FunctionsTestHostBuilder()
    .WithFunctionsAssembly(typeof(MyDurableFunction).Assembly)
    .ConfigureFakeDurableSupport(provider =>
    {
        // Register orchestration runners
        provider.AddOrchestration<string>("MyOrchestrator", ctx => MyOrchestratorFunction.RunAsync(ctx));
    })
    .BuildAndStartAsync();

Coverage

• [DurableClient] DurableTaskClient injection (both direct gRPC and ASP.NET Core integration paths)
• Direct activity invocation via IFunctionsTestHost.InvokeActivityAsync<TResult>(...)
• Fake orchestration scheduling and activity execution
• Sub-orchestrator execution via TaskOrchestrationContext.CallSubOrchestratorAsync<TResult>()
• Custom status via SetCustomStatus(...) and OrchestrationMetadata.ReadCustomStatusAs<T>()
• External events: both wait-then-raise and buffered raise-before-wait flows
• FunctionsDurableClientProvider resolution from FunctionsTestHost.Services

Example

public class DurableFunctionTests : IAsyncLifetime
{
    private IFunctionsTestHost _testHost;

    public async Task InitializeAsync()
    {
        _testHost = await new FunctionsTestHostBuilder()
            .WithFunctionsAssembly(typeof(OrderOrchestrator).Assembly)
            .WithHostBuilderFactory(Program.CreateHostBuilder)
            .ConfigureFakeDurableSupport(provider =>
            {
                provider.AddOrchestration<OrderResult>("OrderOrchestrator",
                    ctx => OrderOrchestratorFunction.RunAsync(ctx));
                provider.AddActivity<string, OrderResult>("ProcessOrder",
                    input => new OrderResult { Success = true, OrderId = input });
            })
            .BuildAndStartAsync();
    }

    [Fact]
    public async Task StartOrder_StartsOrchestration_AndCompletes()
    {
        // Start via HTTP starter function
        using var client = _testHost.CreateHttpClient();
        var response = await client.PostAsync("/api/orders/start", JsonContent.Create(new { orderId = "123" }));
        response.EnsureSuccessStatusCode();

        var instanceId = await response.Content.ReadAsStringAsync();

        // Resolve the durable client and check status
        var durableClient = _testHost.Services
            .GetRequiredService<FunctionsDurableClientProvider>()
            .GetClient();

        var metadata = await durableClient.GetInstanceAsync(instanceId);
        Assert.Equal(OrchestrationRuntimeStatus.Completed, metadata!.RuntimeStatus);
    }

    [Fact]
    public async Task ProcessOrder_Activity_ReturnsResult()
    {
        // Invoke activity directly
        var result = await _testHost.InvokeActivityAsync<OrderResult>("ProcessOrder", "order-123");
        Assert.True(result.Success);
        Assert.Equal("order-123", result.OrderId);
    }

    [Fact]
    public async Task OrderOrchestrator_WithExternalEvent_Completes()
    {
        var durableClient = _testHost.Services
            .GetRequiredService<FunctionsDurableClientProvider>()
            .GetClient() as FakeDurableTaskClient;

        var instanceId = await durableClient!.ScheduleNewOrchestrationInstanceAsync("OrderOrchestrator", "order-123");

        // Raise external event to unblock orchestrator
        await durableClient.RaiseEventAsync(instanceId, "ApprovalReceived", true);

        var metadata = await durableClient.GetInstanceAsync(instanceId);
        Assert.Equal(OrchestrationRuntimeStatus.Completed, metadata!.RuntimeStatus);
    }

    public async Task DisposeAsync()
    {
        await _testHost.StopAsync();
        _testHost.Dispose();
    }
}

References

• Full documentation
• AzureFunctions.TestFramework.Core

License

MIT