Fix non ascii object members

[m-rossi]

I just had an issue with non-ascii-characters in class members (in my case its a column name of a database I access with SQLAlchemy). This PR sets a default encoding for open() as the default seems to be os-dependent, howevers sphinx expects utf8. This fixes my issues on Windows.

I also tried to modify the non-ascii-testcase, however this seems to pass without my fix. If I execute normal sphinx-build during command-line it fails:

sphinx-build . _build
Sphinx v5.1.1 in Verwendung
making output directory... erledigt
loading intersphinx inventory from https://docs.python.org/3/objects.inv...
[autosummary] generating autosummary for: index.rst
[automodsumm] index.rst: found 4 automodsumm entries to generate
building [mo]: targets for 0 po files that are out of date
building [html]: targets for 1 source files that are out of date
updating environment: [new config] 5 added, 0 changed, 0 removed
reading sources... [100%] index                                                onAsciit
C:\Users\USER\path\to\test\api\sphinx_automodapi.tests.example_module.nonascii.NonAscii.rst:13: WARNING: undecodable source characters, replacing with "?": b'      ~NonAscii.get_>>>\xdf<<<\r'
C:\Users\USER\path\to\test\api\sphinx_automodapi.tests.example_module.nonascii.NonAscii.rst:14: WARNING: undecodable source characters, replacing with "?": b'      ~NonAscii.get_>>>\xe4<<<\xf6\xfc\r'
C:\Users\USER\path\to\test\api\sphinx_automodapi.tests.example_module.nonascii.NonAscii.rst:14: WARNING: undecodable source characters, replacing with "?": b'      ~NonAscii.get_\xe4>>>\xf6<<<\xfc\r'
C:\Users\USER\path\to\test\api\sphinx_automodapi.tests.example_module.nonascii.NonAscii.rst:14: WARNING: undecodable source characters, replacing with "?": b'      ~NonAscii.get_\xe4\xf6>>>\xfc<<<\r'
C:\Users\USER\path\to\test\api\sphinx_automodapi.tests.example_module.nonascii.NonAscii.rst:18: WARNING: undecodable source characters, replacing with "?": b'   .. automethod:: get_>>>\xdf<<<\r'
C:\Users\USER\path\to\test\api\sphinx_automodapi.tests.example_module.nonascii.NonAscii.rst:19: WARNING: undecodable source characters, replacing with "?": b'   .. automethod:: get_>>>\xe4<<<\xf6\xfc\r'
C:\Users\USER\path\to\test\api\sphinx_automodapi.tests.example_module.nonascii.NonAscii.rst:19: WARNING: undecodable source characters, replacing with "?": b'   .. automethod:: get_\xe4>>>\xf6<<<\xfc\r'
C:\Users\USER\path\to\test\api\sphinx_automodapi.tests.example_module.nonascii.NonAscii.rst:19: WARNING: undecodable source characters, replacing with "?": b'   .. automethod:: get_\xe4\xf6>>>\xfc<<<\r'
C:\Users\USER\path\to\test\api\sphinx_automodapi.tests.example_module.nonascii.NonAscii.rst:11: WARNING: autosummary: failed to import NonAscii.get_?.
Possible hints:
* AttributeError: type object 'NonAscii' has no attribute 'NonAscii'
* AttributeError: type object 'NonAscii' has no attribute 'get_?'
* ModuleNotFoundError: No module named 'sphinx_automodapi.tests.example_module.nonascii.NonAscii'; 'sphinx_automodapi.tests.example_module.nonascii' is not a package
* ModuleNotFoundError: No module named 'NonAscii'
* ImportError:
C:\Users\USER\path\to\test\api\sphinx_automodapi.tests.example_module.nonascii.NonAscii.rst:11: WARNING: autosummary: failed to import NonAscii.get_???.
Possible hints:
* AttributeError: type object 'NonAscii' has no attribute 'NonAscii'
* AttributeError: type object 'NonAscii' has no attribute 'get_???'
* ModuleNotFoundError: No module named 'sphinx_automodapi.tests.example_module.nonascii.NonAscii'; 'sphinx_automodapi.tests.example_module.nonascii' is not a package
* ModuleNotFoundError: No module named 'NonAscii'
* ImportError:
* KeyError: 'NonAscii'
WARNING: invalid signature for automethod ('get_?')
WARNING: don't know which module to import for autodocumenting 'get_?' (try placing a "module" or "currentmodule" directive in the document, or giving an explicit module name)  
WARNING: don't know which module to import for autodocumenting 'get_???' (try placing a "module" or "currentmodule" directive in the document, or giving an explicit module name)looking for now-outdated files... none found
pickling environment... erledigt
checking consistency... erledigt
preparing documents... erledigt
writing output... [100%] index                                                 nAsciit
generating indices... genindex py-modindex erledigt
writing additional pages... search erledigt
copying static files... erledigt
copying extra files... erledigt
dumping search index in English (code: en)... erledigt
dumping object inventory... erledigt
build abgeschlossen, 14 warnings.

The HTML pages are in _build.

[bsipocz]

Overall looks good, thank you for the fix.

Could you please add an entry to the changelog (CHANGES.rst) to mention the bugfix? Thanks!

[m-rossi]

@bsipocz I had to remove your suggestion with the empty line as the test fail now.

[codecov]

Codecov Report

Merging #153 (e5a52cf) into main (b602fdc) will decrease coverage by 0.12%.
The diff coverage is 71.42%.

@@            Coverage Diff             @@
##             main     #153      +/-   ##
==========================================
- Coverage   89.43%   89.31%   -0.13%     
==========================================
  Files          23       24       +1     
  Lines        1098     1104       +6     
==========================================
+ Hits          982      986       +4     
- Misses        116      118       +2     

Impacted Files	Coverage Δ
sphinx_automodapi/tests/example_module/nonascii.py	66.66% <66.66%> (ø)
sphinx_automodapi/automodsumm.py	85.62% <100.00%> (ø)

📣 Codecov can now indicate which changes are the most critical in Pull Requests. Learn more

[bsipocz]

Thank you @m-rossi!