Wrapr 1.0.29

Dapr Wrapr

Wrapr is a library for Dapr to start and stop a sidecar to support integration testing. It works particularly well with the In Memory pubsub component but can also be used with other components.

E2E pub/sub example

Arrange

await using var sidecar = new Sidecar("integration-test");
await sidecar.Start(with => with
    .ComponentsPath("components-path")
    .DaprGrpcPort(1234) 
    .Args("--log-level", "warn"));

await sidecar.Stop();

Use it in combination with the WebApplicationFactory or the HostBuilder to also host your web application from the test.

new HostBuilder().ConfigureWebHost(app => app
    .UseStartup<Startup>()
    .ConfigureServices(services => services.AddSingleton(service))
    .UseKestrel(options => options.ListenLocalhost(<mark>5555</mark>)))
.Build();

Act

using var client = new DaprClientBuilder()
    .UseGrpcEndpoint("http://localhost:<mark>1234</mark>")
    .Build();

await client
    .PublishEventAsync("my-pubsub", "Demo", new
    {
        Value = 1234
    });

Assert

If you really want to validate the message arrival on the controller action you probably need to stub an underlying service. Since this is an asynchronous operation by default you will need some mechanism for future completion.

I've had great success with my own "future assertion" library hypothesist.

var hypothesis = Hypothesis
    .For<int>()
    .Any(x => x == 1234);

After that you only need a stub that tests the hypothesis before you can validate it. For example using NSubstitute:

service
    .Handle(Arg.Any<int>())
    .Returns(5)
    .AndDoes(x => hypothesis.Test(x.Arg<int>()));

or with a very slim hand-rolled implementation that does exactly that:

private class TestHandler<T> : IHandler<T>
{
    private readonly IHypothesis<T> _hypothesis;

    public TestHandler(IHypothesis<T> hypothesis) => 
        _hypothesis = hypothesis;

    public Task Handle(T input) =>
        _hypothesis.Test(input);
}

Inject that stub into the service collection used by the WebApplicationFactory or HostBuilder. After that you validate the hypothesis of having received a message with specified shape:

await hypothesis
    .Validate(10.Seconds());