4.6: Run pyupgrade without --py3-plus

[hugovk]

• Target the master branch for bug fixes, documentation updates and trivial changes.
• Target the features branch for new features and removals/deprecations.
• Include documentation when adding new features.
• Include new tests or update existing tests when applicable.

Unless your change is trivial or a small documentation fix (e.g., a typo or reword of a small section) please:

• Create a new changelog file in the changelog folder, with a name like <ISSUE NUMBER>.<TYPE>.rst. See changelog/README.rst for details.
• Add yourself to AUTHORS in alphabetical order;

To help with backports, and related to #5275, this runs pyupgrade without --py3-plus on the 4.6-maintenance branch, to minimise the difference between it and the master branch, where pyupgrade has been run (with --py3-plus).

(And run Black.)

[codecov]

Codecov Report

Merging #5387 into 4.6-maintenance will decrease coverage by 7.42%.
The diff coverage is 85.98%.

@@                 Coverage Diff                 @@
##           4.6-maintenance    #5387      +/-   ##
===================================================
- Coverage            94.28%   86.85%   -7.43%     
===================================================
  Files                  115      115              
  Lines                26362    26362              
  Branches              2603     2603              
===================================================
- Hits                 24855    22897    -1958     
- Misses                1178     3110    +1932     
- Partials               329      355      +26

Impacted Files	Coverage Δ
src/_pytest/warnings.py	88.88% <0%> (ø)	⬆️
testing/test_terminal.py	93.62% <100%> (-5.29%)	⬇️
src/_pytest/_io/saferepr.py	80.43% <100%> (ø)	⬆️
src/_pytest/runner.py	96.83% <100%> (-1.19%)	⬇️
src/_pytest/main.py	91.9% <100%> (-3.94%)	⬇️
src/_pytest/debugging.py	90.25% <100%> (ø)	⬆️
testing/test_pdb.py	94.94% <100%> (-3.12%)	⬇️
src/_pytest/assertion/util.py	95.57% <100%> (-2.59%)	⬇️
src/_pytest/helpconfig.py	97.6% <100%> (ø)	⬆️
src/_pytest/reports.py	68.96% <100%> (-26.11%)	⬇️
... and 74 more

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[hugovk]

Ah, tests are failing, if this isn't a quick win it's probably not worth the effort.

By the way, I did test this on my fork before creating the PR, but tests all fail on forks (also for clean master and 4.6-maintenance) maybe due to the repo = pytest-dev/pytest restrictions.

Sorry for the noise, feel free to close!

[nicoddemus]

I will let @asottile comment/handle this one. 😁

[asottile]

Yeah we can't quite do this as pytest 2.7 code isn't quite unicode clean (which is why it was running with --skip-percent-format)

[asottile]

Note that we're already running pyupgrade as well, just with the format fixer disabled