private void TryToTimeSpanFriendly(TimeSpan?expected, string value)
{
String8 value8 = value.TestConvert();
TimeSpan actual;
bool succeeded = value8.TryToTimeSpanFriendly(out actual);
Assert.AreEqual(expected.HasValue, succeeded, $"Success wrong for '{value}'");
Assert.AreEqual(expected ?? TimeSpan.Zero, actual, $"Result wrong for '{value}'");
}