Alba 1.0 – Recipes for ASP.Net Core Integration Testing

A while back I blogged about a new-ish OSS project called Alba that my colleagues and I were building for doing automated integration testing against ASP.Net Core applications. I’ve been working on some of our test automation infrastructure for our ASP.Net Core projects this week, so it was a natural time to document Alba and push it up to a 1.0 release on Nuget. By no means is it “done,” but it’s at the point where I think what’s there is already useful and I’m happy to put the SemVer stake in the ground and lock down the API signatures. While Alba is brand new, it’s based on the older Scenario testing feature we’ve used for a couple years in our prior FubuMVC applications (part of my impetus for building Alba was to make it easier to migrate FubuMVC codebases to ASP.Net Core).

Alright, for a quick start, let’s say that you’re building the obligatory hello, world application in ASP.Net Core:

    public class Startup
    {
        public void Configure(IApplicationBuilder builder)
        {
            builder.Run(context =>
            {
                context.Response.Headers["content-type"] = "text/plain";
                return context.Response.WriteAsync("Hello, World!");
            });
        }
    }

To test the behavior of the root url, you could use Alba within an xUnit test like so:

[Fact]
public Task should_say_hello_world()
{
    using (var system = SystemUnderTest.ForStartup<Startup>())
    {
        // This runs an HTTP request and makes an assertion
        // about the expected content of the response
        return system.Scenario(_ =>
        {
            _.Get.Url("/");
            _.ContentShouldBe("Hello, World!");
            _.StatusCodeShouldBeOk();
        });
    }
}

The test above:

1. Bootstraps the ASP.Net Core application defined by the Startup type
2. Configures the Http request
3. Declares a couple assertions about the expected Http response
4. Executes the Http request by directly invoking the RequestDelegate for the underlying application
5. Runs all of the configured assertions and reports out any failures by throwing an exception that would cause the unit test to fail

There’s plenty more content on the Alba website in the links I’ve listed below:

• The Alba project website and the related documentation.
• The getting started page
• Writing your own custom assertions for Alba
• The code on Github
• There’s a Gitter room you can use to get help or make suggestions for future Alba work
• It isn’t up yet, but I recorded a podcast with the Herding Code guys that talks about Alba (among several other things) that should show up soon.

The next step for Alba is just to try to trick folks into giving it a shot and responding to whatever feedback comes from that;) I will write a follow up soon on how my shop is starting to use Alba within Storyteller for acceptance testing against ASP.Net Core applications.