It would be great to be able to list which methods cause a reference leak.

Example right now on the 3.6 branch:
----
$ ./python -m test -R 3:3 test_os 
Run tests sequentially
0:00:00 [1/1] test_os
beginning 6 repetitions
123456
......
test_os leaked [124, 124, 124] references, sum=372
test_os leaked [114, 114, 114] memory blocks, sum=342
test_os failed in 32 sec

1 test failed:
    test_os

Total duration: 32 sec
Tests result: FAILURE
----

Which methods caused the refleak?

Is it possible to list test methods of a test file using unittest?

First step: I created the issue #30523, "unittest: add --list-tests option to only display the list of test names, don't run tests".

I don't understand how issue30523 and issue30540 can help to resolve this issue.

Serhiy: "I don't understand how issue30523 and issue30540 can help to resolve this issue."

- issue30523 produces a list of all test methods
- issue30540 allows to pass a file to filter tests
- attached bisect_test.py takes an input file produced by --list-tests and uses --matchfile to run tests

Example of usage:

./python bisect_test.py test_tools tests bisect -n 5 

* bisect -R 3:3 on test_tools
* tests contains the list of test identifiers to test_tools
* write result into the file "bisect"
* stop bisection when there is 5 tests or less

The next step is to add a command to regrtest implementing all steps. Or maybe this script is enough? At least, it's enough for my needs ;-)

Updated script: support Windows, fix cmdline help.

Oops, I uploaded the wrong version. It should now work.

New changeset 84d9d14a1fa395fbd21262ba195490be25a7b3bc by Victor Stinner in branch 'master':
bpo-29512: Add test.bisect, bisect failing tests (#2452)
https://github.com/python/cpython/commit/84d9d14a1fa395fbd21262ba195490be25a7b3bc

Ok, I pushed a first implementation. It's problaby buggy and incomplete, but it's better than nothing, and can be enhanced later.

I prefer to play with it longer before starting to backport it to other branches, to not have to backport changes multiple times.

Thanks Yury for the review ;-)

New changeset a3ca94d0504157a112a1f89bfe8be1307116fc73 by Victor Stinner in branch '3.6':
[3.6] bpo-29512, bpo-30776: Backport regrtest enhancements from master to 3.6 (#2513)
https://github.com/python/cpython/commit/a3ca94d0504157a112a1f89bfe8be1307116fc73

New changeset 0b1210739d12c26e4a161ffd494bd572d49b2483 by Victor Stinner in branch '3.5':
[3.5] bpo-29512, bpo-30764, bpo-30776: Backport regrtest enhancements from 3.6 to 3.5 (#2540)
https://github.com/python/cpython/commit/0b1210739d12c26e4a161ffd494bd572d49b2483

New changeset d7955b8196578306e9d86f6c61c9cb3ee72edab0 by Victor Stinner in branch '2.7':
[2.7] bpo-29512, bpo-30764: Backport regrtest enhancements from 3.5 to 2.7 (#2541)
https://github.com/python/cpython/commit/d7955b8196578306e9d86f6c61c9cb3ee72edab0

Ok! "python -m test.bisect" is now available in 2.7, 3.5, 3.6 and master branches ;-)

Maybe it's me who is doing things wrong, but when I run Lib/test/test_httpservers.py I get this strange error :

Traceback (most recent call last):
  File "C:\cpython\Lib\test\test_httpservers.py", line 7, in <module>
    from http.server import BaseHTTPRequestHandler, HTTPServer, \
  File "c:\python36\lib\http\server.py", line 92, in <module>
    import email.utils
  File "c:\python36\lib\email\utils.py", line 28, in <module>
    import random
  File "c:\python36\lib\random.py", line 48, in <module>
    import bisect as _bisect
  File "C:\cpython\Lib\test\bisect.py", line 27, in <module>
    import tempfile
  File "c:\python36\lib\tempfile.py", line 45, in <module>
    from random import Random as _Random
ImportError: cannot import name 'Random'

I see that the bisect module is loaded from location /test/bisect.py because of the script introduced in the resolution of this issue. Is it intentional to give it the same name as a module of the standard library ?

There are many ways of running tests, and some of them are broken now.

$ ./python Lib/test/test_bisect.py
EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE
======================================================================
ERROR: test_backcompatibility (__main__.TestBisectC)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "Lib/test/test_bisect.py", line 34, in setUp
    (self.module.bisect_right, [], 1, 0),
AttributeError: module 'bisect' has no attribute 'bisect_right'

...

Workarounds:

* ./python -m test test_httpservers
* ./python -I Lib/test/test_httpservers.py

> Maybe it's me who is doing things wrong, but when I run Lib/test/test_httpservers.py I get this strange error :

...
  File "c:\python36\lib\random.py", line 48, in <module>
    import bisect as _bisect
  File "C:\cpython\Lib\test\bisect.py", line 27, in <module>
...

Oh. Lib/test/ should not be in sys.path. "import bisect" loaded Lib/test/bisect.py instead of Lib/bisect.py. See my commit 3050987d85d7cf8cdd4b3c053e673d13cd8dfb12 in Python 2.7:

    * regrtest now removes '' and Lib/test/ from sys.path
    * Use absolute import in test_bisect

(regrtest in master already does something similar.)

But the sys.path is only fixed when regrtest is used...


> There are many ways of running tests, and some of them are broken now.
> $ ./python Lib/test/test_bisect.py

... if you run Lib/test/test_xxx.py directly, Lib/test/ is added to sys.path, except if you use -I:

$ ./python -I Lib/test/test_bisect.py 
....................................
----------------------------------------------------------------------
Ran 36 tests in 0.094s

OK


I didn't know that "./python Lib/test/test_bisect.py" was broken :-(

Maybe Lib/test/support/__init__.py can remove Lib/test/ from sys.path?

Another option is to move or rename Lib/test/bisect.py. For example, replace "./python -m test.bisect ..." with "./python -m test bisect ..." (or maybe "./python -m test --bisect ..."). The problem is that bisect has extra options, but we can add a bisect prefix to these options.

I reopen this issue.

New changeset 448c6739877a4143a2c3599f041fa6127f354044 by Victor Stinner in branch '2.7':
bpo-29512: Fix Lib/test/bisect.py shebang (#4522)
https://github.com/python/cpython/commit/448c6739877a4143a2c3599f041fa6127f354044

Python 2.7.14 was released with test.bisect.

While there are corner cases, do we really have to do something?

The simplest fix is just to rename Lib/test/bisect.py to Lib/test/bisect_cmd.py in Python 2.7. It's a tool written for CPython developer, it's CLI is not stable nor documented.

It just mean replacing "./python -m test.bisect ..." with "./python -m test.bisect_cmd ...", not a big deal.

What do you think of renaming the script?

I created the PR 7229 to rename Lib/test/bisect.py to Lib/test/bisect_cmd.py.

New changeset 823c295efa4efea93cadc640ed6122cd9d86cec4 by Victor Stinner in branch '2.7':
bpo-29512: Rename Lib/test/bisect.py to bisect_cmd.py (#7229)
https://github.com/python/cpython/commit/823c295efa4efea93cadc640ed6122cd9d86cec4

One year later, all issues have now been fixed ;-)