Unit testing with Orleans could not find an implementation for interface

Question

I am working on a new application using Microsoft Orleans and .NET 8, and I need to add some tests. I am currently experimenting with Microsoft.Orleans.TestingHost following Unit testing with Orleans

In preparation for the tests, I have created the following fixture:

public sealed class ClusterFixture : IDisposable
{
    public TestCluster Cluster { get; } = new TestClusterBuilder().Build();

    public ClusterFixture() => Cluster.Deploy();

    void IDisposable.Dispose() => Cluster.StopAllSilos();
}

I defined also a collection for my tests:

[CollectionDefinition(Name)]
public sealed class ClusterCollection : ICollectionFixture<ClusterFixture>
{
    public const string Name = nameof(ClusterCollection);
}

My first test looks like this:

[Collection(ClusterCollection.Name)]
public class ClusterTests(ClusterFixture fixture)
{
    private readonly TestCluster _cluster = fixture.Cluster;

    [Fact]
    public async Task Game_Name_Should_Be_Invernomuto()
    {
        var game = _cluster.GrainFactory.GetGrain<IGameGrain>(1);
        var gameInfo = await game.GetState();

        Assert.Equal(CONSTANTS.CLUSTER.GAME_NAME, gameInfo.Name);
    }
}

However, I can't get the test to work:

System.ArgumentException: Could not find an implementation for interface InvernomutoGrainInterfaces.IGameGrain

at Orleans.GrainInterfaceTypeToGrainTypeResolver.GetGrainType(GrainInterfaceType interfaceType) in /_/src/Orleans.Core/Core/GrainInterfaceTypeToGrainTypeResolver.cs:line 102

What am I doing wrong?

Answer 1

The main problem was the missing project reference to the grains implementation in the test project...

Then I discovered that the cluster fixture was missing a proper storage configurator:

public class SiloMemoryStorageConfigurator : ISiloConfigurator
{
    public void Configure(ISiloBuilder hostBuilder)
    {
        hostBuilder.AddMemoryGrainStorage(CONSTANTS.CLUSTER.INVERNOMUTO);
        hostBuilder.AddMemoryGrainStorageAsDefault();
        hostBuilder.AddReminders();
        hostBuilder.UseInMemoryReminderService();
    }
}

when the configurator has been added:

public sealed class ClusterFixture : IDisposable
{
    public TestCluster Cluster { get; } = new TestClusterBuilder
    {
        Options = { ServiceId = Guid.NewGuid().ToString() }
    }
    .AddSiloBuilderConfigurator<SiloMemoryStorageConfigurator>()
    .Build();

    public ClusterFixture() => Cluster.Deploy();

    void IDisposable.Dispose() => Cluster.StopAllSilos();
}

the test works