Troubleshooting

Common issues and solutions when using Skugga.

"Cannot mock sealed classes" (SKUGGA001)

//  Won't work -- sealed class
public sealed class EmailService { }
var mock = Mock.Create<EmailService>(); // Error!

//  Use interfaces instead
public interface IEmailService { }
var mock = Mock.Create<IEmailService>(); // Works!

"Class has no virtual members" (SKUGGA002)

//  Won't work -- non-virtual members
public class EmailService {
   public string GetEmail() => "";
}

//  Make members virtual
public class EmailService {
   public virtual string GetEmail() => "";
}

Generated Code Not Updating

# Clean and rebuild
dotnet clean && dotnet build

The source generator caches output. A clean build forces regeneration.

Setup Not Matching

//  Exact match required
mock.Setup(x => x.GetData(1)).Returns("one");
mock.GetData(2); // Returns null -- no match

//  Use It.IsAny<T>() for flexible matching
mock.Setup(x => x.GetData(It.IsAny<int>())).Returns("any");
mock.GetData(2); // Returns "any"

Interceptors Not Working

Ensure your .csproj has:

<PropertyGroup>
   <InterceptorsPreviewNamespaces>
       $(InterceptorsPreviewNamespaces);Skugga
   </InterceptorsPreviewNamespaces>
</PropertyGroup>

IDE Not Showing Generated Code

Some IDEs need a restart after adding Skugga. Try:

1. Close IDE
2. dotnet clean && dotnet build
3. Reopen IDE

Async Methods Returning null

In Loose mode, un-setup async methods return completed Task/Task<T> with default values (not null Task). If you're getting NullReferenceException:

// Ensure setup returns a Task
mock.Setup(x => x.GetDataAsync()).ReturnsAsync("value");

Native AOT Build Errors

Skugga is designed for AOT. If you see trimming warnings:

1. Ensure you're using the latest Skugga version
2. Check that IsAotCompatible is set correctly in your project
3. Run dotnet publish -r <rid> /p:PublishAot=true to verify