Locale coercion tests on Solaris are failing because 646 ASCII alias is not recognized. Its addition into the _handle_output_variations function fixes this problem.This was changed/fixed in Python 3.8 and later, where aliases are correctly translated to their canonical Python codec name so no patch is needed there.

test_c_locale_coerce should use "codecs.lookup(encoding).name" to get the normalized name of an encoding, rather than fragile:        data = data.replace(b"ANSI_X3.4-1968", b"ascii")        data = data.replace(b"US-ASCII", b"ascii")the proposed pattern is even more dangerous:         data = data.replace(b"646", b"ascii")I'm not sure where encodings should be normalized. Maybe around _check_child_encoding_details().For the PR, please write it for the master branch.

I just added that in the way it was already there but I see why the current solution is not the best. Also I wanted to push this into 3.7 only as this problem is not present in 3.8 (as discussed in thePR 11195 opened incorrectly against the master).Just to be sure: what you propose is to rewrite current replaces to use "codecs.lookup(encoding).name" instead and then push it into the master?Ok, I will look into it.

>  what you propose is to rewrite current replaces to use "codecs.lookup(encoding).name" instead and then push it into the master?I suggest to remove the code which does the .replace(), but instead normalize the encoding when checking for the expected encoding (near .assertEqual()). I still see the .replace() code in master, so yeah, the code should first be changed in master:    @staticmethod    def _handle_output_variations(data):        """Adjust the output to handle platform specific idiosyncrasies        * Some platforms report ASCII as ANSI_X3.4-1968        * Some platforms report ASCII as US-ASCII        * Some platforms report UTF-8 instead of utf-8        """        data = data.replace(b"ANSI_X3.4-1968", b"ascii")        data = data.replace(b"US-ASCII", b"ascii")        data = data.lower()        return data

Python 3.8+ encodings are always normalized and thus no output variations handling is necessary (the code is no longer necessary).Python 3.7 (and possibly lower) can have variations in encodings - that should be fixed with codecs.lookup functions.

New changesetc53173aa00689aa1be17ce5406289718f6b30532 by Victor Stinner (Jakub Kulík) in branch '3.7':bpo-37335: Fix test_c_locale_coercion to handle any ASCII alias (GH-14449)https://github.com/python/cpython/commit/c53173aa00689aa1be17ce5406289718f6b30532

New changeset61bf97e91620e020939d57a36918ab22579920ff by Victor Stinner (Jakub Kulík) in branch 'master':bpo-37335, test_c_locale_coercion: Remove unnecessary code (GH-14447)https://github.com/python/cpython/commit/61bf97e91620e020939d57a36918ab22579920ff

New changeset518dc94e423398f7b0b5fd7bd5b84f138618e68e by Miss Islington (bot) in branch '3.8':bpo-37335, test_c_locale_coercion: Remove unnecessary code (GH-14447)https://github.com/python/cpython/commit/518dc94e423398f7b0b5fd7bd5b84f138618e68e

Thanks Jakub Kulik. test_c_locale_coercion should pass again on 3.7, 3.8 and master branches on Solaris.