Getting DataSource object right is very difficult

[nohwnd]

Description

I was trying to get the new UI in VS for data driven tests. And getting the object for the data source to correctly serialize is so painful.

My contains other objects and getting it to work took me a lot of time.

Is there any additional guidance on this? Or a method that can check if the type is eligible for the new UI?

From what I see:

• Get Set properties need to be used, and default constructor must be present.
• [Serialize] needs to be used for all the objects.
• Abstract class must not be used.
• When inheriting, the objects must be produced exactly using the type that is used in the data source object, but not as any child class.
• Using records or readonly record struct does not make this easier.
• I could not get it to work when there was a collection on the object, but I might be just confused by some other edge case that was preventing me from getting this to work at the same time.

e.g. This works:

[Serializable]
public class OtherInfo : OtherInfoBase { 
}

[Serializable]
public class OtherInfoBase { 
    public string Name {get; set;}
}

[Serializable]
public class RunnerInfo { 
    public string Name {get; set;}
    public OtherInfo {get; set;}
}

BUT making the RunnerInfo use the Base class, it only works when we assign the BaseClass itself, but not if we create OtherInfo and assign it:

[Serializable]
public class OtherInfo : OtherInfoBase { 
}

[Serializable]
public class OtherInfoBase { 
    public string Name {get; set;}
}

[Serializable]
public class RunnerInfo { 
    public string Name {get; set;}
    public OtherInfoBase {get; set;}
}

[Evangelink]

@nohwnd What kind of data source are you referring to? Could you provide a more complete example?

[ghost]

This issue has been automatically marked as stale because it has been marked as requiring author feedback but has not had any activity for 4 days. It will be closed if no further activity occurs within 10 days of this comment.

[nohwnd]

DataSource like the one here: https://github.com/microsoft/vstest/blob/3fac63690f8cd14e2681470639b15c527c3d09ff/test/Microsoft.TestPlatform.AcceptanceTests/ExecutionTests.cs#L21

Once your parameter is not a primitive type (RunnerInfo in the case above) it gets really difficult to make sure MSTest will expand it to multiple test cases using the new top level expansion. You need to balance all the things listed above.

[stan-sz]

@Evangelink - Is this something that can be checked with a MSTest analyzer?

[nohwnd]

After working for a while on the codebase I think this mostly boils down to the serializer that is used. It would be pretty difficult to enforce the rules by analyzer, and custom data sources are imho not that used to warrant that investment.