Ok, thanks @ecolban, it is fixed now. I just could not understand the random test, but looking at the structure of your ascii tree it makes sense now.

My problem was indeed that I popped from the input array a (sorry @Blind4Basics !)

No, the random seed is not the same and the input list a is different each time. This not an error.

No, I made a copy before passing to my function:
tree = a.copy()

I just don't get how the last test can work (unless the random seed is the same each time):
Test.it('Random ten nodes')
a = [randrange(10) for i in range(10)]
Test.assert_equals(complete_binary_tree(a), [a[i] for i in [6, 3, 8, 1, 5, 7, 9, 0, 2, 4]])

I bet you mutated the input array? => if so, the problem is in your code, actually.

@ecolban: you should send a copy to the user. Same for the random tests.

Yes, sorry. In the last python test I get this error with exit code 1:

Traceback (most recent call last):
File "main.py", line 13, in
Test.assert_equals(complete_binary_tree(a), [a[i] for i in [6, 3, 8, 1, 5, 7, 9, 0, 2, 4]])
File "main.py", line 13, in
Test.assert_equals(complete_binary_tree(a), [a[i] for i in [6, 3, 8, 1, 5, 7, 9, 0, 2, 4]])
IndexError: list index out of range

Thanks!

Can you be a little more specific about what the problem is?

I tweaked the same algorithm and submitted as Javascript, which worked.
Please fix the last Python test case.

Why is this marked fixed. My python test is failing on the random test.

Why is this marked fixed. My python test is failing on the random test.