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. Recently, nevertheless, I have been utilizing the quicker and usually extra appropriate Playwright. It has one API and may take a look at on Home windows, Linux, Mac, domestically, in a container (headless), in my CI/CD pipeline, on Azure DevOps, or in GitHub Actions.
For me, it is that final second of reality to guarantee that the positioning runs utterly from finish to finish.
I can write these Playwright checks in one thing like TypeScript, and I may launch them with node, however I like operating finish unit checks and utilizing that take a look at runner and take a look at harness as my leaping off level for my .NET purposes. I am used to proper clicking and “run unit checks” and even higher, proper click on and “debug unit checks” in Visible Studio or VS Code. This will get me the advantage of the entire 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 checks after which launching Selenium. This was form of janky and would require to manually begin a separate course of and handle its life cycle. Nonetheless, I saved on with this hack for various years principally attempting to get the Kestrel Internet Server to spin up inside my unit checks.
I’ve not too long ago upgraded my fundamental website and podcast website to .NET 8. Take into account that I have been transferring my web sites ahead from early early variations of .NET to the latest 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 checks 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 Important(string[] args)
{
CreateWebHostBuilder(args).Construct().Run();
}public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseStartup<Startup>();
to this:
public static void Important(string[] args)
{
CreateHostBuilder(args).Construct().Run();
}public static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args).
ConfigureWebHostDefaults(WebHostBuilder => WebHostBuilder.UseStartup<Startup>());
Not a serious change on the skin however tidies issues up on the within and units me up with a extra versatile generic host for my net app.
My unit checks stopped working as a result of my Kestral Internet Server hack was now not firing up my server.
Right here is an instance of my objective from a Playwright perspective inside a .NET NUnit take a look at.
[Test]
public async Process DoesSearchWork()
{
await Web page.GotoAsync(Url);await Web page.Locator("#topbar").GetByRole(AriaRole.Hyperlink, new() { Title = "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 Count on(Web page.Locator(visibleCards).First).ToBeVisibleAsync();
await Count on(Web page.Locator(visibleCards)).ToHaveCountAsync(5);
}
I like this. Good and clear. Definitely right here we’re assuming that we’ve a URL in that first line, which will likely 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 take a look at builder manufacturing facility,” yeah, the title is silly nevertheless it’s descriptive. Word the OneTimeSetUp and the OneTimeTearDown. This begins my net app inside the context of my TestHost. Word the :0 makes the app discover a port which I then, sadly, must dig out and put into the Url personal to be used inside my Unit Checks. Word that the <Startup> 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<Startup>();var startup = new Startup(builder.Setting);
builder.WebHost.ConfigureKestrel(o => o.Hear(IPAddress.Loopback, 0));
startup.ConfigureServices(builder.Providers);
_app = builder.Construct();// hear on any native port (therefore the 0)
startup.Configure(_app, _app.Configuration);
_app.Begin();//you're kidding me
Url = _app.Providers.GetRequiredService<IServer>().Options.GetRequiredFeature<IServerAddressesFeature>().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 remainder 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<T>() the place T : class
{
//This ungodly code requires an unused reference to the MvcTesting package deal 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 Title is null");
var contentRootPath = json?[asmFullName]?.GetValue<string>();//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 strains are nasty. As a result of the take a look at 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 drive the content material root path to be appropriate and the one method to do this is by getting the apps base listing from a file generated inside MSBuild from the (ageing) MvcTesting package deal. The package deal shouldn’t be 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 will eliminate that “hack” and pull the listing from context elsewhere, then this helper perform turns right into a single line and .NET 9 will get WAY WAY extra testable!
Now I can run my Unit Checks AND Playwright Browser Integration Checks throughout all OS’s, headed or headless, in docker or on the steel. The location is up to date to .NET 8 and all is correct with my code. Properly, it runs at the least. 😉
About Scott
Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, guide, father, diabetic, and Microsoft worker. He’s a failed stand-up comedian, a cornrower, and a guide writer.
