test_intersphinx_all_mappings is unstable

[benjaoming]

There was a test error, and I re-ran the tests and they pass on the second attempt.

It seems test_intersphinx_all_mappings is unstable?

py38-sphinx24 create: /home/circleci/project/.tox/py38-sphinx24
py38-sphinx24 installdeps: pytest, pdbpp, sphinxcontrib-bibtex, ., sphinx~=2.4.0, docutils<0.18, jinja2<3.1.0
py38-sphinx24 inst: /home/circleci/project/.tox/.tmp/package/1/sphinx-hoverxref-1.1.3.tar.gz
py38-sphinx24 installed: alabaster==0.7.12,attrs==22.1.0,Babel==2.10.3,certifi==2022.9.24,charset-normalizer==2.1.1,docutils==0.17.1,fancycompleter==0.9.1,idna==3.4,imagesize==1.4.1,importlib-metadata==5.0.0,iniconfig==1.1.1,Jinja2==3.0.3,latexcodec==2.0.1,MarkupSafe==2.1.1,packaging==21.3,pdbpp==0.10.3,pluggy==1.0.0,py==1.11.0,pybtex==0.24.0,pybtex-docutils==1.0.2,Pygments==2.13.0,pyparsing==3.0.9,pyrepl==0.9.0,pytest==7.1.3,pytz==2022.4,PyYAML==6.0,requests==2.28.1,six==1.16.0,snowballstemmer==2.2.0,Sphinx==2.4.5,sphinx-hoverxref @ file:///home/circleci/project/.tox/.tmp/package/1/sphinx-hoverxref-1.1.3.tar.gz,sphinxcontrib-applehelp==1.0.2,sphinxcontrib-bibtex==2.5.0,sphinxcontrib-devhelp==1.0.2,sphinxcontrib-htmlhelp==2.0.0,sphinxcontrib-jsmath==1.0.1,sphinxcontrib-qthelp==1.0.3,sphinxcontrib-serializinghtml==1.1.5,tomli==2.0.1,urllib3==1.26.12,wmctrl==0.4,zipp==3.8.1
py38-sphinx24 run-test-pre: PYTHONHASHSEED='3359466892'
py38-sphinx24 run-test: commands[0] | pytest
============================= test session starts ==============================
platform linux -- Python 3.8.14, pytest-7.1.3, pluggy-1.0.0
cachedir: .tox/py38-sphinx24/.pytest_cache
rootdir: /home/circleci/project, configfile: pytest.ini
collecting ... collected 14 items                                                             

tests/test_htmltag.py ............F                                      [ 92%]
tests/test_internals.py .                                                [100%]

=================================== FAILURES ===================================
________________________ test_intersphinx_all_mappings _________________________

app = <SphinxTestApp buildername='html'>
status = <_io.StringIO object at 0x7f0964a5f790>
warning = <_io.StringIO object at 0x7f096491b820>

    @pytest.mark.sphinx(
        srcdir=intersphinxsrc,
        confoverrides={
            'hoverxref_intersphinx': [
                'readthedocs',
                'python',
            ],
            'hoverxref_intersphinx_types': {
                'readthedocs': 'modal',
                'python': {
                    'class': 'modal',
                }
            },
            'hoverxref_domains': ['py'],
            'default_role': 'obj',
        },
    )
    def test_intersphinx_all_mappings(app, status, warning):
        app.build()
        path = app.outdir / 'index.html'
        assert path.exists() is True
        content = open(path).read()
    
        chunks_regex = [
            # Python's links do have hoverxref enabled
            r'<a class="hxr-hoverxref hxr-tooltip reference external" href="https://docs.python.org/3/tutorial/index.html#tutorial-index" title="\(in Python v3.\d\d?\)"><span class="xref std std-ref">This a :ref: to The Python Tutorial using intersphinx</span></a>',
            r'<a class="hxr-hoverxref hxr-tooltip reference external" href="https://docs.python.org/3/library/datetime.html#datetime-datetime" title="\(in Python v3.\d\d?\)"><span class="xref std std-ref">This a :ref: to datetime.datetime Python’s function using intersphinx</span></a>',
            r'<a class="hxr-hoverxref hxr-modal reference external" href="https://docs.python.org/3/library/functions.html#float" title="\(in Python v3.\d\d?\)"><code class="xref py py-class docutils literal notranslate"><span class="pre">float</span></code></a>',
    
            # Read the Docs' link does have hoverxref enabled
            r'<a class="hxr-hoverxref hxr-modal reference external" href="https://docs.readthedocs.io/en/stable/config-file/v2.html#python" title="\(in Read the Docs user documentation v\d\d?.\d\d?.\d+\)"><span class="xref std std-ref">This a :ref: to Config File v2 Read the Docs’ page using intersphinx</span></a>',
    
            # Using `default_role = 'obj'`
            # Note the difference with the same `float` line previouly. Here it uses `py-obj` instead of `py-class`.
            r'<a class="hxr-hoverxref hxr-tooltip reference external" href="https://docs.python.org/3/library/functions.html#float" title="\(in Python v3.\d\d?\)"><code class="xref py py-obj docutils literal notranslate"><span class="pre">float</span></code></a>'
        ]
    
        chunks = [
            # Python domain's link does have hoverxref enabled
            '<a class="hxr-hoverxref hxr-tooltip reference internal" href="#hoverxref.extension.setup" title="hoverxref.extension.setup"><code class="xref py py-func docutils literal notranslate"><span class="pre">hoverxref.extension.setup()</span></code></a>',
        ]
    
        for chunk in chunks:
            assert chunk in content
    
        for chunk in chunks_regex:
>           assert re.search(chunk, content)
E           assert None
E            +  where None = <function search at 0x7f09696a0dc0>('<a class="hxr-hoverxref hxr-modal reference external" href="https://docs.readthedocs.io/en/stable/config-file/v2.html...\d+\\)"><span class="xref std std-ref">This a :ref: to Config File v2 Read the Docs’ page using intersphinx</span></a>', '\n<!DOCTYPE html>\n\n<html xmlns="http://www.w3.org/1999/xhtml">\n  <head>\n    <meta charset="utf-8" /><meta name="g...ref="_sources/index.rst.txt"\n          rel="nofollow">Page source</a>\n    </div>\n\n    \n\n    \n  </body>\n</html>')
E            +    where <function search at 0x7f09696a0dc0> = re.search

tests/test_htmltag.py:373: AssertionError
--------------------------- Captured stdout teardown ---------------------------

Originally posted by @benjaoming in #234 (comment)