I believe the file “correct answers.xaml” as supplied in the Resource zip should have the scope of the variable “text” set to the “While” activity so the failures will occur as described in the walkthrough. However, at least in the file I downloaded today (September 17, 2017), the scope of “text” already set to "Process one file."
Also, the failures will not occur unless you either remove or rename the files “3.txt” and “5.txt”, something not mentioned in the walkthrough, although I guess it’s obvious enough.
The final file will not look correct unless the final carriage return and line feed are removed from “3.txt”, because there will be an extra line appended.
None of these omissions are critical, and this is a very useful and necessary lesson. I would actually like to see more material on debugging, since that’s what we spend so much time doing.