Make tests more PyPy compatible

[serhiy-storchaka]

BPO	25130
Nosy	@terryjreedy, @cfbolz, @benjaminp, @ambv, @vadmium, @serhiy-storchaka, @rlamy, @miss-islington
PRs	bpo-25130: Add calls of gc.collect() in tests to support PyPy #28005 bpo-25130: Make unit-test about restricting the maximum number of nested blocks cpython-only #28002 [3.10] bpo-25130: Make unit-test about restricting the maximum number of nested blocks cpython-only (GH-28002) #28016 [3.9] bpo-25130: Make unit-test about restricting the maximum number … #28017 bpo-25130: Make SQLite tests more compatible with PyPy #28021 [3.10] bpo-25130: Make SQLite tests more compatible with PyPy (GH-28021) #28022 [3.9] bpo-25130: Make SQLite tests more compatible with PyPy (GH-28021) #28023 [3.10] bpo-25130: Add calls of gc.collect() in tests to support PyPy (GH-28005). #28027 [3.9] bpo-25130: Add calls of gc.collect() in tests to support PyPy (GH-28005). #28028
Files	pypy_tests_gc_collect-2.7.patch: Just add gc.collect() calls pypy_tests-2.7_full.patch: Full difference between 2.7 tests in PyPy and CPython

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/serhiy-storchaka'
closed_at = None
created_at = <Date 2015-09-15.18:15:24.258>
labels = ['type-feature', 'tests', '3.9', '3.10', '3.11']
title = 'Make tests more PyPy compatible'
updated_at = <Date 2021-09-08.15:09:06.833>
user = 'https://github.com/serhiy-storchaka'

bugs.python.org fields:

activity = <Date 2021-09-08.15:09:06.833>
actor = 'lukasz.langa'
assignee = 'serhiy.storchaka'
closed = False
closed_date = None
closer = None
components = ['Tests']
creation = <Date 2015-09-15.18:15:24.258>
creator = 'serhiy.storchaka'
dependencies = []
files = ['40475', '40481']
hgrepos = []
issue_num = 25130
keywords = ['patch']
message_count = 18.0
messages = ['250789', '250812', '250816', '250824', '250832', '250835', '250836', '389367', '400439', '400492', '400496', '400497', '400519', '400520', '400522', '400523', '400526', '401387']
nosy_count = 9.0
nosy_names = ['terry.reedy', 'Carl.Friedrich.Bolz', 'benjamin.peterson', 'lukasz.langa', 'fijall', 'martin.panter', 'serhiy.storchaka', 'Ronan.Lamy', 'miss-islington']
pr_nums = ['28005', '28002', '28016', '28017', '28021', '28022', '28023', '28027', '28028']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue25130'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']

[serhiy-storchaka]

PyPy includes modified Python 2.7 tests for testing compatibility. Some of changes skips tests for features that are not implemented in PyPy or are CPython specific, some reflects differences between error types or messages in CPython and PyPy, some are needed because PyPy doesn't use reference counting, some are workarounds for known PyPy or CPython bugs. The purpose of this issue is to port harmless non PyPy-specific changes. I'll split full patch on several parts for easier review.

The first patch in a series just adds gc.collect() or test.test_support.gc_collect() calls to force calling destructors or freeing memory.

[vadmium]

Left some comments. There are a few test cases that I suspect are relying on side effects of garbage collection to perform some other test, and it would be better to rework the test. In the other cases, I agree that actual garbage collection behaviour is being tested, and it makes sense to call gc_collect() or similar.

[serhiy-storchaka]

Thank you for your comments Martin. I need a time to think over them and provide alternative solutions that less depend on garbage collecting. May be Maciej can answer questions about causes of some PyPy changes.

[serhiy-storchaka]

Just for reference here is a full difference between 2.7 tests in PyPy and CPython. It makes tests fail in CPython and skips some tests or makes them too lenient.

[fijall]

Hi

I can answer precise questions, which tests are you asking about?

Note that if the point is to unify the test suite, would be cool to make changes to both pypy and cpython and not just change cpython one.

[vadmium]

Maciej: I put a few questions and comments in the code review. See the <https://bugs.python.org/review/25130/#ps15551\> (also linked next to Serhiy’s first patch).

[fijall]

Hi

Looking through your comments, yes, maybe those tests or those things require fixing. We at pypy don't have enough will to fight python-dev most of the time, so the usual approach is to do "minimal hack that works" without trying to dwelve into why this or that works that way. Obviously feel free to fix the underlaying issue, we'll be happy to commit it to pypy

[terryjreedy]

With 2.7 EOL, is this still relevant?

[serhiy-storchaka]

Unfortunately Martin's comments are not available now, after shutting down the Rietveld service.

Here is a new PR which contains extraction of PyPy changes related to calling gc.collect() for 3.8. I removed changes which look specific for PyPy and left changes which look common for every implementation without reference counting.

[serhiy-storchaka]

New changeset eb263f9 by Carl Friedrich Bolz-Tereick in branch 'main':
bpo-25130: Make unit-test about restricting the maximum number of nested blocks cpython-only (GH-28002)
eb263f9

[serhiy-storchaka]

New changeset 779b9ae by Miss Islington (bot) in branch '3.10':
bpo-25130: Make unit-test about restricting the maximum number of nested blocks cpython-only (GH-28002) (GH-28016)
779b9ae

[serhiy-storchaka]

New changeset 1046cd0 by Serhiy Storchaka in branch '3.9':
[3.9] bpo-25130: Make unit-test about restricting the maximum number of nested blocks cpython-only (GH-28002) (GH-28017)
1046cd0

[serhiy-storchaka]

New changeset 07d3d54 by Serhiy Storchaka in branch 'main':
bpo-25130: Make SQLite tests more compatible with PyPy (GH-28021)
07d3d54

[miss-islington]

New changeset a49398b by Miss Islington (bot) in branch '3.10':
bpo-25130: Make SQLite tests more compatible with PyPy (GH-28021)
a49398b

[serhiy-storchaka]

New changeset dab74d6 by Serhiy Storchaka in branch '3.9':
[3.9] bpo-25130: Make SQLite tests more compatible with PyPy (GH-28021) (GH-28023)
dab74d6

[serhiy-storchaka]

New changeset 2a8127c by Serhiy Storchaka in branch 'main':
bpo-25130: Add calls of gc.collect() in tests to support PyPy (GH-28005)
2a8127c

[serhiy-storchaka]

New changeset 330aabb by Serhiy Storchaka in branch '3.9':
[3.9] bpo-25130: Add calls of gc.collect() in tests to support PyPy (GH-28005). (GH-28028)
330aabb

[ambv]

New changeset 462c1f0 by Serhiy Storchaka in branch '3.10':
[3.10] bpo-25130: Add calls of gc.collect() in tests to support PyPy (GH-28005) (GH-28027)
462c1f0