The question is looking for the number of times you performed multiplication, not the end result of the multiplication.

the same 'edge case' test block was testing the 1,2,3,4 list with 4 items per page at first, then with 1, hence a mismatch between the name of the test block and the assertion messages for the latter. i moved the tests with 1 item per page to their own block

[...] returns its multiplicative persistence, which is the number of times you must multiply the digits in num until you reach a single digit.

You misunderstood the task, please reread the description.