How to use DependencyInjection in BenchmarkDotNet?

Question

I'd like to use BenchmarkDotNet on some legacy code I'm working with right now. It is written in C# Net462. It is a big, old and complex system and I'd like to Benchmark some methods inside some specific class. Those classes use dependency injection and I'm not sure how I could do it. All the examples I've seen so far are not using any dependency injection.

Does anyone have any ideas or examples I could have a look?

Thank you very much.

Answer 1

You need to create the dependency injection container in the ctor or a method with [GlobalSetup] attribute, resolve the type that you want to benchmark and store it in a field. Then use it in a benchmark and dispose the DI container in a [GlobalCleanup] method.

Pseudocode:

public class BenchmarksDI
{
    private IMyInterface _underTest;
    private IDependencyContainer _container;
    
    [GlobalSetup]
    public void Setup()
    {
        _container = CallYourCodeThatBuildsDIContainer();
        _underTest = _container.Resolve<IMyInterface>();
    }
    
    [Benchmark]
    public void MethodA() => _underTest.MethodA();
    
    [GlobalCleanup]
    public void Cleanup() => _container.Dispose();
}