Dependency Injection

Prova features a built-in, zero-reflection dependency injection system designed for speed and Native AOT compatibility.

Concept

Unlike other frameworks that rely on Microsoft.Extensions.DependencyInjection (which is heavy on reflection), Prova uses a lightweight, source-generated approach. You register services using explicit factory delegates, and the test runner automatically wires them into your test constructors.

Quick Start

1. Define Services

public interface ICalculator { int Add(int a, int b); }
public class Calculator : ICalculator 
{ 
    public int Add(int a, int b) => a + b; 
}

2. Configure dependencies

Create a static method marked with [ConfigureServices]. This is your composition root.

using Prova.Core;
using Prova.Core.Attributes;

public static class Setup
{
    [ConfigureServices]
    public static void Configure(ProvaServiceProvider services)
    {
        // Transient: Created new every time
        services.AddTransient<ICalculator>(() => new Calculator());

        // Singleton: Created once (Lazy)
        services.AddSingleton<IDatabase>(() => new InMemoryDatabase());
    }
}

3. Inject into Tests

Simply request the dependencies in your test constructor.

public class MathTests
{
    private readonly ICalculator _calculator;

    public MathTests(ICalculator calculator)
    {
        _calculator = calculator;
    }

    [Fact]
    public void CanAdd()
    {
        Assert.Equal(4, _calculator.Add(2, 2));
    }
}

Service Lifetimes

Lifetime	Method	Description
Transient	AddTransient<T>(Func<T>)	A new instance is created every time it is injected.
Singleton	AddSingleton<T>(Func<T>)	A single instance is created the first time it is requested and reused for all subsequent tests.

FAQ

Q: Can I use Microsoft.Extensions.DependencyInjection? A: Not directly in the core test runner, because Prova prioritizes AOT support. However, you can register a wrapper service that talks to an IServiceProvider if you really need to bridge the two worlds.

Q: Does it support Scoped services (per-test)? A: Currently, only Singleton and Transient are supported. Scoped support is planned for a future release.