Tests .NET/C# systems at their integration boundaries — HTTP APIs with `WebApplicationFactory<T>`, EF Core against real databases via Testcontainers (PostgreSQL, SQL Server, Redis), Blazor/Razor Pages in real browsers via `Microsoft.Playwright`, Avalonia UI via `Avalonia.Headless.XUnit`. Works with
Tests .NET/C# systems at their integration boundaries — HTTP APIs with `WebApplicationFactory<T>`, EF Core against real databases via Testcontainers (PostgreSQL, SQL Server, Redis), Blazor/Razor Pages in real browsers via `Microsoft.Playwright`, Avalonia UI via `Avalonia.Headless.XUnit`. Works with xUnit v2/v3 on VSTest or Microsoft.Testing.Platform. Use when building or debugging anything that cr