I’ve found the issue with the second error regarding the my_exe command… it was completely my own fault, as I didn’t realize that I was calling strtok one extra time before actually starting going over the directories, effectively removing the first element in the PATH variable…
Sorry everyone 
However, there’s still the issue of:
[tester::#MG5] Expected: "cp is /bin/cp"
[tester::#MG5] Received: "cp is /usr/bin/cp"
I still have no idea why this is a happening.