[issue10161] unittest: use ascii() instead of repr() to display values on error

[STINNER Victor]

New submission from STINNER Victor <victor.stinner at haypocalc.com>:

On a failure, unittest does its best to display values. But sometimes, the output doesn't help me. Example:

FAIL: test_listdir (test.test_pep277.UnicodeFileTests)
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Traceback (most recent call last):
  File "/Users/db3l/buildarea/3.x.bolen-tiger/build/Lib/test/test_pep277.py", line 157, in test_listdir
    self.assertEqual(sf0, sf2)
AssertionError: Items in the first set but not the second:
'@test_18608_tmp/ ̈́ΎΫ'
'@test_18608_tmp/ẛ῁῍῎῏῝῞῟῭'
Items in the second set but not the first:
'@test_18608_tmp/ ̈́ΥΎ̈'
'@test_18608_tmp/ẛ῁῍῎᾿῾῾῾῁̀́͂̀'
'@test_18608_tmp/΅ϒϓ̈'

This is a test on unicode filenames. I would prefer to see non-ASCII characters as \xHH or \uXXXX than strange characters or boxes.

Do you think that it is a good idea to replace calls to repr() by ascii() in the unittest library?

In Python2, repr(unicode) escapes all non-ASCII characters. But in Python3, only control characters and surrogates are escaped. So the output depends on the terminal encoding.

Write non-ASCII characters in a backtrace may also raise a new error if the terminal is unable to a character. Raise an error while printing an error is just horrible :-)

--

Attached patch is a try to replace repr() by ascii() in the unittest module. But I don't know this library, so don't trust the patch :-)

----------
components: Library (Lib), Unicode
files: unittest_ascii.patch
keywords: patch
messages: 119248
nosy: haypo
priority: normal
severity: normal
status: open
title: unittest: use ascii() instead of repr() to display values on error
versions: Python 3.2
Added file: http://bugs.python.org/file19311/unittest_ascii.patch

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue10161>
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