Using LazyInject in UnitTests

Hi, is it possible to use LazyInject within UnitTests? I tried something like the following and _foo in class Bar (line 13) is always null when executing the UnitTest. I already played around with the order of binding and couldn’t solve this.

Best regards 😃

using System;
using System.Threading.Tasks;
using Zenject;

public class Bar : BarBase, IBar {
    LazyInject<Foo> _foo;

    public Bar(LazyInject<Foo> foo) {
        _foo = foo;
    }

    public async Task<bool> Run() {
        return await _foo.Value.Run();
    }

    public void Register(Action<bool> callback) {
        int a = 5 + 2;
        callback.Invoke(true);
    }
}

public class BarBase {
    public BarBase() { }
}

using System;
using System.Threading.Tasks;

public interface IBar {
    Task<bool> Run();
    void Register(Action<bool> callback);
}

using System.Threading.Tasks;

public class Foo : IFoo {
    public async Task<bool> Run() {
        await Task.Delay(1000);
        return true;
    }
}

using System.Threading.Tasks;

public interface IFoo {
    Task<bool> Run();
}

using Moq;
using NUnit.Framework;
using System;
using Zenject;

[TestFixture]
public class FooBarUnitTest : ZenjectUnitTestFixture {

    [Inject]
    IBar _bar;
    [Inject]
    IFoo _foo;

    [SetUp]
    public void CommonInstall() {

        Container.Bind<IFoo>().To<Foo>().AsSingle();

        Mock<IBar> bar = new Mock<Bar>(_foo).As<IBar>();
        bar.CallBase = true;
        bar.Setup(b => b.Register(It.IsAny<Action<bool>>()))
            .Callback<Action<bool>>(async (action) => {
                action.Invoke(await bar.Object.Run());
            }
        );

        Container.BindInstance(bar.Object).AsSingle();
        Container.Inject(this);
    }

    [Test]
    public void TestInitialValues() {
        bool wasRunning = _bar.Run().GetAwaiter().GetResult();

        Assert.True(wasRunning);
    }
}

[svermeulen]

I think it has something to do with your async code though, not zenject. Maybe check into what SynchronizationContext you’re using, since that will determine how code is continued after an await

[FireDragonGameStudio]

Found the issue! The error is caused by Unitys old NUnit version (https://forum.unity.com/threads/async-await-in-unittests.513857/) The execution of async await in UnitTests is… different.

Thank you for pointing me into the right direction 😃 Correct test looks now like this:

using NUnit.Framework;
using System.Threading.Tasks;
using Zenject;

[TestFixture]
public class FooBarUnitTest : ZenjectUnitTestFixture {

    [Inject]
    IBar _bar;

    [SetUp]
    public void CommonInstall() {
        Container.Bind<Foo>().AsSingle();
        Container.Bind<IBar>().To<Bar>().AsSingle();
        Container.Inject(this);
    }

    [Test]
    public void TestInitialValues() {

        bool wasRunning = false;

        wasRunning = Task.Run(() => _bar.Run()).GetAwaiter().GetResult();

        Assert.True(wasRunning);
    }
}

Best regards 😃