public static TheoryData <T1, T2> PopulateFrom <T1, T2>(this TheoryData <T1, T2> testData, IEnumerable <(T1, T2)> source)
public static IEnumerable <T> ToEnumerable <T>(this TheoryData <T> theoryData)
{
return(theoryData.Select(d => (T)d[0]));
}