1453850 - Enable Python 2's `-3` mode on Travis

Status: RESOLVED FIXED

(Tree Management :: Treeherder, enhancement, P2)

Description

[Ed Morley [:emorley]]

Passing the `-3` option to Python 2 switches on DeprecationWarnings about Python 3 incompatibilities:
https://docs.python.org/2/using/cmdline.html#cmdoption-3

By using `-3` mode on Travis, it will help prevent regressions in the Python 3 fixes that have already landed.

This mode already helped find one real issue that affects us even under Python 2 (bug 1453837).

Comment 1

[GitHub Bugzilla PR Linker]

Attachment: Link to GitHub pull-request: https://github.com/mozilla/treeherder/pull/3444

Comment 2

[Treeherder GitHub Bugbot]

Commit pushed to master at https://github.com/mozilla/treeherder

https://github.com/mozilla/treeherder/commit/023d31885a8c9d421450713a871e6576c85794a8
Bug 1453850 - Enable Python 2's `-3` mode on Travis (#3444)

This enables `DeprecationWarnings` for things that Python 2 knows
are not compatible with Python 3. The `error` entry in the pytest
`filterwarnings` setting ensures these will be surfaced as Exceptions
and so result in test failures.

See:
https://docs.python.org/2/using/cmdline.html#cmdoption-3

The removal of `sorted()` from `test_bug_job_map_api.py` is to fix:
`DeprecationWarning: dict inequality comparisons not supported in 3.x`