assertCountEqual is a horribly misleading name because it misleads the programmer and reader of the test code into thinking that it only compares the counts of the elements.

It's name misrepresents what it does in a really bad way.

Hey Vitaly, not sure if you're the author of the original bug here: https://bugs.python.org/issue27071

Could you re-open that so the discussion is kept in one place.

Re-opened, thanks!

On Fri, Sep 20, 2019 at 3:01 PM Ammar Askar <report@bugs.python.org> wrote:

>
> Ammar Askar <ammar@ammaraskar.com> added the comment:
>
> Hey Vitaly, not sure if you're the author of the original bug here:
> https://bugs.python.org/issue27071
>
> Could you re-open that so the discussion is kept in one place.
>
> ----------
> nosy: +ammar2
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <https://bugs.python.org/issue38240>
> _______________________________________
>

Reopened per request from ammar2

This should stay closed as a duplicate.

If you must, reopen of the original 27071, but it was closed for a reason.  The majority of respondents voted for the status quo.  Each alternative that was considered had its own share of problems.

BTW, it is hyperbolic to call the name "horribly misleading".  The method literally runs Counter and checks for equality.  The docstring is clear about this:

    def assertCountEqual(self, first, second, msg=None):
        """Asserts that two iterables have the same elements, the same number of
        times, without regard to order.

            self.assertEqual(Counter(list(first)),
                             Counter(list(second)))

         Example:
            - [0, 1, 1] and [1, 0, 1] compare equal.
            - [0, 0, 1] and [0, 1] compare unequal.

        """

Well, when you do tab-completion in unit tests on `self.` and
`assertCountEqual` pops up, it sure sounds a lot like it's going to compare
just the count of the items. The point is that the name of the function is
not self-documenting, hence "misleading".

A better name could be `assertItemsEqual` or `assertCountAndItemsEqual`

On Sat, Sep 5, 2020 at 1:02 PM Raymond Hettinger <report@bugs.python.org>
wrote:

>
> Raymond Hettinger <raymond.hettinger@gmail.com> added the comment:
>
> This should stay closed as a duplicate.
>
> If you must, reopen of the original 27071, but it was closed for a
> reason.  The majority of respondents voted for the status quo.  Each
> alternative that was considered had its own share of problems.
>
> BTW, it is hyperbolic to call the name "horribly misleading".  The method
> literally runs Counter and checks for equality.  The docstring is clear
> about this:
>
>     def assertCountEqual(self, first, second, msg=None):
>         """Asserts that two iterables have the same elements, the same
> number of
>         times, without regard to order.
>
>             self.assertEqual(Counter(list(first)),
>                              Counter(list(second)))
>
>          Example:
>             - [0, 1, 1] and [1, 0, 1] compare equal.
>             - [0, 0, 1] and [0, 1] compare unequal.
>
>         """
>
> ----------
> nosy: +rhettinger
> status: open -> closed
>
> _______________________________________
> Python tracker <report@bugs.python.org>
> <https://bugs.python.org/issue38240>
> _______________________________________
>

Vitaly, when you repost to posts by email, please delete the post you are responding to, expect possible for a particular line.  The full post is already here on the web page above the response, and a duplicate copy is just noise that wastes screen space.