Windows

WinAppEngine drives a Windows app through Windows UI Automation. WinUI 3, WPF, WinForms, and Win32 apps all expose it. The engine runs on Windows only and needs no other tool installed.

Prerequisites

• Windows 10 or 11 and the .NET 10 SDK.
• An unlocked, interactive desktop. Keys, clicks, and the wheel go to the window in the foreground, so a locked screen or a CI runner without a desktop session fails them with NOT_ACTIONABLE.
• An app the engine can start: an unpackaged build, such as WinUI 3 with WindowsPackageType set to None, WPF, or WinForms.

1. Create the test project

dotnet new nunit -n MyApp.E2ETests
cd MyApp.E2ETests
dotnet add package E2E.WinApp.NUnit      # or E2E.WinApp.XUnit.V3

A test project on plain net10.0 also needs this, because the UI Automation library ships Windows assets only. Without it, restore fails with NU1202. Or target net10.0-windows.

<PropertyGroup>
  <AssetTargetFallback>$(AssetTargetFallback);net10.0-windows7.0</AssetTargetFallback>
  <NoWarn>$(NoWarn);NU1701</NoWarn>
</PropertyGroup>

2. Point at your app

Set AutomationId on every control a test touches (AutomationProperties.AutomationId in XAML).

{
  "targets": [
    {
      "name": "myapp",
      "platform": "windows",
      "app": {
        "appPath": "../MyApp/bin/x64/Debug/net10.0-windows10.0.22621.0/MyApp.exe",
        "bundleId": "MyApp"
      }
    }
  ],
  "actionTimeout": 15000,
  "assertionTimeout": 10000,
  "agents": { "default": { "provider": "copilot", "model": "claude-sonnet-5.5", "context": "MyApp is a settings editor." } },
  "cache": { "dir": ".e2e/cache" }
}

appPath is the executable, relative to the folder of e2e.config.json. bundleId is the app’s process name. E2E_WINAPP_APP_PATH names another executable without editing the config.

3. Write a test

Derive from WinAppTest. It launches the app fresh before each test, ends it after, and gives the agent the open_app and alert tools.

using E2E.WinApp.NUnit;

[assembly: Category("Windows")]
[assembly: NonParallelizable]   // one window in the foreground at a time

public sealed class LoginTests : WinAppTest
{
    [Test]
    public async Task Signs_in()
    {
        await Screen.GetByTestId("email-input").FillAsync("tester@tester.army");
        await Screen.GetByTestId("password-input").FillAsync("benchmark123");
        await Screen.GetByTestId("login-button").TapAsync();

        await Expect.That(Screen.GetByTestId("success-message")).ToHaveTextAsync("Logged in successfully");
    }

    [Test]
    [Category("RealModel")]
    public async Task The_agent_signs_in()
    {
        await Agent.ActAsync("sign in as {email}", new ActOptions
        {
            Params = new Dictionary<string, object?> { ["email"] = "tester@tester.army" },
        });

        await Expect.That(Screen.GetByTestId("success-message")).ToBeVisibleAsync();
    }
}

Roles follow the browser vocabulary: a Button is button, an edit is textbox, a ToggleSwitch is switch, a ContentDialog is dialog. Window is the window fixture: ResizeAsync, MaximizeAsync, CloseAppAsync, OpenAppAsync, and AlertAsync(AlertAction.Accept).

4. Run

dotnet test --project .
dotnet test --project . --filter "TestCategory!=RealModel"   # no model

Known limits

No video, App.BackAsync is UNSUPPORTED_CAPABILITY (tap the app’s own Back button), and a screenshot is the main window only.

Next

WinApp benchmarkA WinUI 3 app of hard scenarios and its tests.