private string GetRelativePath(CallInfo callInfo, CalamariPhysicalFileSystem realFileSystem)
{
//nsubstitute calls the first return when you setup a second one. odd.
if (callInfo.ArgAt <string>(0) == null)
{
return(null);
}
return(realFileSystem.GetRelativePath(callInfo.ArgAt <string>(0), callInfo.ArgAt <string>(1)));
}
