I have been doing not simply Unit Testing for my websites however full on Integration Testing and Browser Automation Testing as early as 2007 with Selenium. These days, nonetheless, I have been utilizing the sooner and customarily extra appropriate Playwright. It has one API and may check on Home windows, Linux, Mac, regionally, in a container (headless), in my CI/CD pipeline, on Azure DevOps, or in GitHub Actions.

For me, it is that final second of fact to be sure that the positioning runs fully from finish to finish.

I can write these Playwright assessments in one thing like TypeScript, and I might launch them with node, however I like operating finish unit assessments and utilizing that check runner and check harness as my leaping off level for my .NET purposes. I am used to proper clicking and “run unit assessments” and even higher, proper click on and “debug unit assessments” in Visible Studio or VS Code. This will get me the advantage of all the assertions of a full unit testing framework, and all the advantages of utilizing one thing like Playwright to automate my browser.

In 2018 I used to be utilizing WebApplicationFactory and a few difficult hacks to principally spin up ASP.NET inside .NET (on the time) Core 2.1 inside the unit assessments after which launching Selenium. This was type of janky and would require to manually begin a separate course of and handle its life cycle. Nevertheless, I stored on with this hack for a variety of years principally making an attempt to get the Kestrel Internet Server to spin up inside my unit assessments.

I’ve lately upgraded my most important website and podcast website to .NET 8. Needless to say I have been transferring my web sites ahead from early early variations of .NET to the newest variations. The weblog is fortunately operating on Linux in a container on .NET 8, however its unique code began in 2002 on .NET 1.1.

Now that I am on .NET 8, I scandalously found (as my unit assessments stopped working) that the remainder of the world had moved from IWebHostBuilder to IHostBuilder 5 model of .NET in the past. Gulp. Say what you’ll, however the backward compatibility is spectacular.

As such my code for Program.cs modified from this

public static void Most important(string[] args)
{
CreateWebHostBuilder(args).Construct().Run();
}
public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseStartup();

to this:

public static void Most important(string[] args)
{
CreateHostBuilder(args).Construct().Run();
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args).
ConfigureWebHostDefaults(WebHostBuilder => WebHostBuilder.UseStartup());

Not a significant change on the surface however tidies issues up on the within and units me up with a extra versatile generic host for my net app.

My unit assessments stopped working as a result of my Kestral Internet Server hack was not firing up my server.

Right here is an instance of my aim from a Playwright perspective inside a .NET NUnit check.

[Test]
public async Process DoesSearchWork()
{
await Web page.GotoAsync(Url);
await Web page.Locator("#topbar").GetByRole(AriaRole.Hyperlink, new() { Identify = "episodes" }).ClickAsync();
await Web page.GetByPlaceholder("search and filter").ClickAsync();
await Web page.GetByPlaceholder("search and filter").TypeAsync("spouse");
const string visibleCards = ".showCard:seen";
var ready = await Web page.WaitForSelectorAsync(visibleCards, new PageWaitForSelectorOptions() { Timeout = 500 });
await Anticipate(Web page.Locator(visibleCards).First).ToBeVisibleAsync();
await Anticipate(Web page.Locator(visibleCards)).ToHaveCountAsync(5);
}

I like this. Good and clear. Definitely right here we’re assuming that we’ve got a URL in that first line, which might be localhost one thing, after which we assume that our net software has began up by itself.

Right here is the setup code that begins my new “net software check builder manufacturing facility,” yeah, the title is silly nevertheless it’s descriptive. Notice the OneTimeSetUp and the OneTimeTearDown. This begins my net app inside the context of my TestHost. Notice the :0 makes the app discover a port which I then, sadly, need to dig out and put into the Url personal to be used inside my Unit Exams. Notice that the is actually my Startup class inside Startup.cs which hosts my app’s pipeline and Configure and ConfigureServices get setup right here so routing all works.

personal string Url;
personal WebApplication? _app = null;
[OneTimeSetUp]
public void Setup()
{
var builder = WebApplicationTestBuilderFactory.CreateBuilder();
var startup = new Startup(builder.Atmosphere);
builder.WebHost.ConfigureKestrel(o => o.Pay attention(IPAddress.Loopback, 0));
startup.ConfigureServices(builder.Providers);
_app = builder.Construct();
// pay attention on any native port (therefore the 0)
startup.Configure(_app, _app.Configuration);
_app.Begin();
//you're kidding me
Url = _app.Providers.GetRequiredService().Options.GetRequiredFeature().Addresses.Final();
}
[OneTimeTearDown]
public async Process TearDown()
{
await _app.DisposeAsync();
}

So what horrors are buried in WebApplicationTestBuilderFactory? The primary bit is unhealthy and we should always repair it for .NET 9. The remaining is definitely each good, with a hat tip to David Fowler for his assist and steerage! That is the magic and the ick in a single small helper class.

public class WebApplicationTestBuilderFactory 
{
public static WebApplicationBuilder CreateBuilder() the place T : class 
{
//This ungodly code requires an unused reference to the MvcTesting bundle that hooks up
//  MSBuild to create the manifest file that's learn right here.
var testLocation = Path.Mix(AppContext.BaseDirectory, "MvcTestingAppManifest.json");
var json = JsonObject.Parse(File.ReadAllText(testLocation));
var asmFullName = typeof(T).Meeting.FullName ?? throw new InvalidOperationException("Meeting Full Identify is null");
var contentRootPath = json?[asmFullName]?.GetValue();
//spin up an actual dwell net software inside TestHost.exe
var builder = WebApplication.CreateBuilder(
new WebApplicationOptions()
{
ContentRootPath = contentRootPath,
ApplicationName = asmFullName
});
return builder;
}
}

The primary 4 traces are nasty. As a result of the check runs within the context of a unique listing and my web site must run inside the context of its personal content material root path, I’ve to power the content material root path to be appropriate and the one approach to try this is by getting the apps base listing from a file generated inside MSBuild from the (growing older) MvcTesting bundle. The bundle isn’t used, however by referencing it it will get into the construct and makes that file that I then use to drag out the listing.

If we are able to do away with that “hack” and pull the listing from context elsewhere, then this helper operate turns right into a single line and .NET 9 will get WAY WAY extra testable!

Now I can run my Unit Exams AND Playwright Browser Integration Exams throughout all OS’s, headed or headless, in docker or on the metallic. The location is up to date to .NET 8 and all is correct with my code. Properly, it runs a minimum of.

About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, advisor, father, diabetic, and Microsoft worker. He’s a failed stand-up comedian, a cornrower, and a guide creator.

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