Rename test_... functions to avoid the naming scheme reserved by pytest

[mkoeppe]

sage -t throws errors on some files because pytest is configured to look for methods prefixed with test_ and treats them as pytest test functions/methods, which are then executed. However, sage's code base contains some functions that match this pattern without being pytests.

This leads to problems like

$ ./sage -tp src/sage/tests/cmdline.py
too many failed tests, not using stored timings
Running doctests with ID 2022-03-20-11-46-21-1dc8fb11.
Using --optional=4ti2,buckygen,ccache,cryptominisat,debugpy,e_antic,gap_packages,homebrew,igraph,jupymake,latte_int,libsemigroups,lidia,lrslib,meataxe,normaliz,pip,polytopes_db_4d,pynormaliz,sage,sage_spkg,texttable
Features to be detected: 4ti2,benzene,bliss,buckygen,conway_polynomials,csdp,database_cremona_ellcurve,database_cremona_mini_ellcurve,database_jones_numfield,database_knotinfo,dvipng,graphviz,imagemagick,jupymake,kenzo,latte_int,lrslib,mcqd,meataxe,nauty,palp,pandoc,pdf2svg,pdftocairo,plantri,polytopes_db,polytopes_db_4d,pynormaliz,python_igraph,rubiks,sage.combinat,sage.geometry.polyhedron,sage.graphs,sage.groups,sage.plot,sage.rings.number_field,sage.rings.padics,sage.rings.real_double,sage.symbolic,sage_numerical_backends_coin,sagemath_doc_html,sphinx,tdlib
Doctesting 1 file using 8 threads.
sage -t --random-seed=23402257756506608859254049173870803147 src/sage/tests/cmdline.py
...
=================================================================================== test session starts ===================================================================================
platform darwin -- Python 3.10.2, pytest-7.0.1, pluggy-1.0.0
rootdir: /Users/mkoeppe/s/sage/sage-rebasing/worktree-gcc11/src, configfile: tox.ini
collected 1 item                                                                                                                                                                          

src/sage/tests/cmdline.py E                                                                                                                                                         [100%]

========================================================================================= ERRORS ==========================================================================================
____________________________________________________________________________ ERROR at setup of test_executable ____________________________________________________________________________
file /Users/mkoeppe/s/sage/sage-rebasing/worktree-gcc11/src/sage/tests/cmdline.py, line 61
  def test_executable(args, input="", timeout=100.0, pydebug_ignore_warnings=False, **kwds):
E       fixture 'args' not found
>       available fixtures: add_imports, cache, capfd, capfdbinary, caplog, capsys, capsysbinary, doctest_namespace, monkeypatch, pytestconfig, record_property, record_testsuite_property, record_xml_attribute, recwarn, tmp_path, tmp_path_factory, tmpdir, tmpdir_factory
>       use 'pytest --fixtures [testpath]' for help on them.

/Users/mkoeppe/s/sage/sage-rebasing/worktree-gcc11/src/sage/tests/cmdline.py:61
================================================================================= short test summary info =================================================================================
ERROR src/sage/tests/cmdline.py::test_executable
==================================================================================== 1 error in 0.01s =====================================================================================

We fix it in this ticket as follows:

• If the offending function is a proper (sage) test function, then change its name from test_xyz to _test_xyz (which also marks them as private)
• If the offending function is a "real" user-faced function, then explicitly exclude it from pytests test discovery.

See #31924 for further discussion on different approaches to fix the same issue including their pros and cons.

This is preparation for #33546.

Depends on #32975
Depends on #33612
Depends on #33617

CC: @tobiasdiez

Component: refactoring

Author: Tobias Diez

Branch/Commit: public/tests/pytest_wrong_test_methods @ 7644854

Reviewer: Sebastian Oehms, Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/33549

[slel]

comment:2

Good thing pycheck and pyright let us use
check_... and right_...! : )

[tobiasdiez]

Description changed:

--- 
+++ 
@@ -1,3 +1,41 @@
-As suggested in [#31924 comment:37](https://github.com/sagemath/sage/issues/31924#comment:37)
+`sage -t` throws errors on some files because pytest is configured to look for methods prefixed with `test_` and treats them as pytest test functions/methods, which are then executed. However, sage's code base contains some functions that match this pattern without being pytests.
+
+This leads to problems like
+
+```
+$ ./sage -tp src/sage/tests/cmdline.py
+too many failed tests, not using stored timings
+Running doctests with ID 2022-03-20-11-46-21-1dc8fb11.
+Using --optional=4ti2,buckygen,ccache,cryptominisat,debugpy,e_antic,gap_packages,homebrew,igraph,jupymake,latte_int,libsemigroups,lidia,lrslib,meataxe,normaliz,pip,polytopes_db_4d,pynormaliz,sage,sage_spkg,texttable
+Features to be detected: 4ti2,benzene,bliss,buckygen,conway_polynomials,csdp,database_cremona_ellcurve,database_cremona_mini_ellcurve,database_jones_numfield,database_knotinfo,dvipng,graphviz,imagemagick,jupymake,kenzo,latte_int,lrslib,mcqd,meataxe,nauty,palp,pandoc,pdf2svg,pdftocairo,plantri,polytopes_db,polytopes_db_4d,pynormaliz,python_igraph,rubiks,sage.combinat,sage.geometry.polyhedron,sage.graphs,sage.groups,sage.plot,sage.rings.number_field,sage.rings.padics,sage.rings.real_double,sage.symbolic,sage_numerical_backends_coin,sagemath_doc_html,sphinx,tdlib
+Doctesting 1 file using 8 threads.
+sage -t --random-seed=23402257756506608859254049173870803147 src/sage/tests/cmdline.py
+...
+=================================================================================== test session starts ===================================================================================
+platform darwin -- Python 3.10.2, pytest-7.0.1, pluggy-1.0.0
+rootdir: /Users/mkoeppe/s/sage/sage-rebasing/worktree-gcc11/src, configfile: tox.ini
+collected 1 item                                                                                                                                                                          
+
+src/sage/tests/cmdline.py E                                                                                                                                                         [100%]
+
+========================================================================================= ERRORS ==========================================================================================
+____________________________________________________________________________ ERROR at setup of test_executable ____________________________________________________________________________
+file /Users/mkoeppe/s/sage/sage-rebasing/worktree-gcc11/src/sage/tests/cmdline.py, line 61
+  def test_executable(args, input="", timeout=100.0, pydebug_ignore_warnings=False, **kwds):
+E       fixture 'args' not found
+>       available fixtures: add_imports, cache, capfd, capfdbinary, caplog, capsys, capsysbinary, doctest_namespace, monkeypatch, pytestconfig, record_property, record_testsuite_property, record_xml_attribute, recwarn, tmp_path, tmp_path_factory, tmpdir, tmpdir_factory
+>       use 'pytest --fixtures [testpath]' for help on them.
+
+/Users/mkoeppe/s/sage/sage-rebasing/worktree-gcc11/src/sage/tests/cmdline.py:61
+================================================================================= short test summary info =================================================================================
+ERROR src/sage/tests/cmdline.py::test_executable
+==================================================================================== 1 error in 0.01s =====================================================================================
+```
+
+We fix it in this ticket as follows:
+- If the offending function is a proper (sage) test function, then change its name from `test_xyz` to `_test_xyz` (which also marks them as private)
+- If the offending function is a "real" user-faced function, then explicitly exclude it from pytests test discovery.
+
+See #31924 for further discussion on different approaches to fix the same issue including their pros and cons. 
 
 This is preparation for #33546.

[tobiasdiez]

Branch: public/tests/pytest_wrong_test_methods

[tobiasdiez]

Commit: 7060ea1

[tobiasdiez]

Author: Tobias Diez

[tobiasdiez]

Changed dependencies from #31924 to none

[tobiasdiez]

New commits:

59cabaa	Make test methods private
ba26086	Hide remaining methods starting with test from pytest
3dc0f63	Cleanup cmdline
321bd9d	Revert changes in test_class_pickling
db1d505	Fix tests in sageinspect
a09d5ec	Fix test_long
7060ea1	Fix imports in modular decomposition

[soehms]

comment:4

Yo should have a look at:

sage -t --warn-long 126.1 --random-seed=123007730607096856939441742800394041101 src/sage/tests/cmdline.py
**********************************************************************
File "src/sage/tests/cmdline.py", line 313, in sage.tests.cmdline._test_executable
Failed example:
    out.find("All tests passed!") >= 0
Expected:
    True
Got:
    False
**********************************************************************
File "src/sage/tests/cmdline.py", line 316, in sage.tests.cmdline._test_executable
Failed example:
    ret
Expected:
    0
Got:
    2
**********************************************************************
1 item had failures:
   2 of 217 in sage.tests.cmdline._test_executable
    [216 tests, 2 failures, 190.78 s]

and

sage -t --warn-long 125.1 --random-seed=216213492016970842904386788649176794439 src/sage/rings/tests.py
**********************************************************************
File "src/sage/rings/tests.py", line 416, in sage.rings.tests.?
Failed example:
    sage.rings.tests._test_karatsuba_multiplication(ZZ, 6, 5, verbose=True, seed=42)
Expected:
    _test_karatsuba_multiplication: ring=Univariate Polynomial Ring in x over Integer Ring, threshold=2
    (2*x^6 - x^5 - x^4 - 3*x^3 + 4*x^2 + 4*x + 1)*(4*x^4 + x^3 - 2*x^2 - 20*x + 3)
      (16*x^2)*(-41*x + 1)
      (x^6 + 2*x^5 + 8*x^4 - x^3 + x^2 + x)*(-x^2 - 4*x + 3)
      (-x^3 - x - 8)*(-1)
      (x - 1)*(-x^5 + 3*x^4 - x^3 + 2*x + 1)
      (x^3 + x^2 + x + 1)*(4*x^3 + 76*x^2 - x - 1)
      (x^6 - 5*x^4 - x^3 + 6*x^2 + 1)*(5*x^2 - x + 4)
      (3*x - 2)*(x - 1)
      (21)*(14*x^5 - x^2 + 4*x + 1)
      (12*x^5 - 12*x^2 + 2*x + 1)*(26*x^4 + x^3 + 1)
Got:
    test_karatsuba_multiplication: ring=Univariate Polynomial Ring in x over Integer Ring, threshold=2
      (2*x^6 - x^5 - x^4 - 3*x^3 + 4*x^2 + 4*x + 1)*(4*x^4 + x^3 - 2*x^2 - 20*x + 3)
      (16*x^2)*(-41*x + 1)
      (x^6 + 2*x^5 + 8*x^4 - x^3 + x^2 + x)*(-x^2 - 4*x + 3)
      (-x^3 - x - 8)*(-1)
      (x - 1)*(-x^5 + 3*x^4 - x^3 + 2*x + 1)
      (x^3 + x^2 + x + 1)*(4*x^3 + 76*x^2 - x - 1)
      (x^6 - 5*x^4 - x^3 + 6*x^2 + 1)*(5*x^2 - x + 4)
      (3*x - 2)*(x - 1)
      (21)*(14*x^5 - x^2 + 4*x + 1)
      (12*x^5 - 12*x^2 + 2*x + 1)*(26*x^4 + x^3 + 1)
**********************************************************************
1 item had failures:
   1 of   7 in sage.rings.tests.?
    [54 tests, 1 failure, 20.02 s]

[sagetrac-git]

Changed commit from 7060ea1 to dec7b7b

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

dec7b7b

Fix doctest in rings