src/sage/env.py: canonicalize paths in a test

[orlitzky]

A test in sage.env is running sage in a subprocess to compare the values of SAGE_ROOT and SAGE_LOCAL. It does the comparison as strings, however, and can fail:

File "src/sage/env.py", line 14, in sage.env
Failed example:
    out == repr((SAGE_ROOT, SAGE_LOCAL))   # long time
Expected:
    True
Got:
    False

This despite the fact that both values are equivalent:

sage: out
"('/home/mjo/src/sage.git/src/sage/../..', '/usr')"
sage: repr((SAGE_ROOT, SAGE_LOCAL))
"('/home/mjo/src/sage.git', '/usr')"

We update the test to canonicalize the paths within the subprocess, and output only "True" or "False" instead.

[orlitzky]

Oh, so that's why it was using f-string substitution for a command with no variables...

Linting files... ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 100% 0:00:09
╭─ Error: namespace_pkg_all_import: import from .all of a namespace package ───╮
│      9     sage: env = {k:v for (k,v) in os.environ.items() if not k.starts  │
│     10     sage: from subprocess import check_output                         │
│  ❱  11     sage: cmd  =  "from sage.all import SAGE_ROOT, SAGE_LOCAL;"       │

[github-actions]

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[orlitzky]

CI is an unrelated timeout:

----------------------------------------------------------------------
sage -t --long --random-seed=286735480429121101562228604801325644303 src/sage/coding/linear_code.py  # Timed out
----------------------------------------------------------------------

I'm going to start shamelessly plugging,

• Use CPU time for --warn-long #36226

On every ticket where the CI "fails" due to slow tests.

[antonio-rojas]

This breaks the test on distro builds where SAGE_ROOT is not defined

> /usr/bin/python -c "from sage.all import SAGE_ROOT, SAGE_LOCAL;from os.path import samefile;s1 = samefile(SAGE_ROOT, 'None');"

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "<frozen genericpath>", line 112, in samefile
TypeError: stat: path should be string, bytes, os.PathLike or integer, not NoneType