Week 4 Assignment 1 - Unknown test failing

I have completed the assignment and for each part of the assignment the check is returning “All tests passed.”

but in the auto-grader is returning

“Tests failed on 1 cell(s)! These tests could be hidden. Please check your submission.” so I am getting 90%.

I’ve tried restarting the kernel and rerunning the whole code but the checks still returns “All tests passed” and the expected output matches for all tests.

How can I find which test is the one failing?

Why is a test failing if the expected output matches the output?

The tests in the notebook are not strong enough to catch all possible errors. Sorry that the grader does not give more useful feedback in this case. Believe me, we have asked the course staff about this, but apparently it is not so easy to change.

The types of errors to look for are referencing global variables instead of the parameters being passed in or making fixed “hard coded” assumptions about the shapes or dimensions of any of the objects.