Source generator files cannot specify encoding, verification fails due to encoding

[kzu]

File contents are indeed the same, but I get:

   System.InvalidOperationException : Context: Source generator application
   Context: Verifying source generated files
   encoding of 'StructId.Analyzer\StructId.ParsableGenerator\UserId.parsable.cs' was expected to be '' but was 'utf-8'

This happens regardless of how the generator adds the file (as string content, as SourceText, with or without encoding).
Since the test set up cannot specify the encoding of the generated files, it seems it's impossible to have them match:

        var test = new CSharpSourceGeneratorTest<ParsableGenerator, DefaultVerifier>
        {
            ReferenceAssemblies = ReferenceAssemblies.Net.Net80,
            TestState =
            {
                Sources =
                {
                    """
                    // ...
                    """,
                },
                GeneratedSources =                 
                {
                    (@"StructId.Analyzer\StructId.ParsableGenerator\UserId.parsable.cs", 
                    // 👇 how to specify encoding here??
                    "// expected file contents"
                },
            },
        };

        await test.RunAsync();

It's weird that two overloads that only differ in passing the generator type (or not), would default to different encodings:

https://github.com/dotnet/roslyn-sdk/blob/main/src/Microsoft.CodeAnalysis.Testing/Microsoft.CodeAnalysis.Analyzer.Testing/SourceFileCollection.cs#L16-L25

[Youssef1313]

@kzu You can already specify the encoding:

GeneratedSources =
{
    (@"StructId.Analyzer\StructId.ParsableGenerator\UserId.parsable.cs", 
    SourceText.From("// expected file contents", encoding))
}