TUnit 0.3.0 has broken my test code

[Patrick8639]

Hello everybody,

I have converted all my test code from xUnit to TUnit and it works great under version 0.2.212.
Updating TUnit to version 3.0.x makes my test code not compiling, all the errors being when using the MethodDataSource attribute.

Here is an example of what doesn't work:

The base class for all my JSON values is defined as:

public abstract class JsonValue

To test casting to a JsonBooleanValue, I have the following test:

  public static IEnumerable <JsonValue> InvalidCastValues () =>
  [
    new JsonArrayValue    (null),
    new JsonDateValue     (null, Date.Today ()),
    new JsonDateTimeValue (null, DateTime.Now),
    new JsonDoubleValue   (null, 0.0),
    new JsonInt32Value    (null, 0),
    new JsonInt64Value    (null, 0),
    new JsonObjectValue   (new JsonInt32Value ("a", 0))
  ];



  [Test]
  [MethodDataSource (nameof (InvalidCastValues))]
  public async Task Cast_FromInvalidValue (
    JsonValue json
  ) =>
    await Assert.That (() => _ = (Boolean) json).ThrowsExactly <ArgumentException> ();

This code compiles well with TUnit 0.2.212, but, under TUnit 0.3.xxxI have the following errors:

Error CS1503 : Argument 1: cannot convert from 'System.Collections.Generic.List<OrdinaSoft.Json.JsonValue>' to 'OrdinaSoft.Json.JsonValue'
Warning TUnit0046 : Return a Func<T> rather than a <T>.

I've tried to change the data source method to the following, but I still have compilation errors:

  public static IEnumerable <Func <JsonValue>> InvalidCastValues () =>
  [
    static () => new JsonArrayValue    (null),
    static () => new JsonDateValue     (null, Date.Today ()),
    static () => new JsonDateTimeValue (null, DateTime.Now),
    static () => new JsonDoubleValue   (null, 0.0),
    static () => new JsonInt32Value    (null, 0),
    static () => new JsonInt64Value    (null, 0),
    static () => new JsonObjectValue   (new JsonInt32Value ("a", 0))
  ];

In the MethodDataSoruce atrribute - Error TUnit0001 : Attribute argument types 'System.Collections.Generic.List<OrdinaSoft.Json.JsonValue>' don't match method parameter types 'OrdinaSoft.Json.JsonValue'

And also errors in the test method.

I've also tried to use yield return in my data source, but with the same errors.

I'm currently out of ideas to make this work. Does somebody knows what's wrong?

[thomhurst]

Sounds like a bug in a recent refactor @Patrick8639.

Could you produce me a minimal repro? I've tried myself with a simple example but it's not giving me any errors:

using TUnit.Assertions;
using TUnit.Assertions.Extensions;

namespace TUnit.TestProject;

public class Repro
{    
    [Test]
    [MethodDataSource(nameof(MethodWithBaseReturn))]
    public void DataSource_WithBaseReturn(BaseValue value)
    {
    }

    public static IEnumerable<Func<BaseValue>> MethodWithBaseReturn() =>
    [
        () => new ConcreteValue(),
        () => new ConcreteValue2()
    ];
    
    public abstract class BaseValue;

    public class ConcreteValue : BaseValue;
    public class ConcreteValue2 : BaseValue;
}

[thomhurst]

Your error message says you're returning a System.Collections.Generic.List, but your code says IEnumerable - Did you change it?

[Patrick8639]

@thomhurst If you have a private place, I can give you the source code of the classes and the tests.

[Patrick8639]

@thomhurst

Your error message says you're returning a System.Collections.Generic.List, but your code says IEnumerable - Did you change it?

Sorry for this: I have multiple tests like that (one for each different data type) and forget to convert one of them to IEnumerable. After changing it, the tests compile but I still have the following warning:

Warning TUnit0046 : Return a Func rather than a .

If I change the InvalidCastValues to return IEnumerable <Func <JsonValue>>, I have the error in the MethodDataSource attribute.
But the tests run without any error!

[Patrick8639]

So the only problem that remains is the following error displayed in Rider:

[thomhurst]

Can you try v0.3.29?

[Patrick8639]

Can you try v0.3.29?

It works perfectly with version 0.3.29.
Thanks for the good work.