Run Sphinx tests with current Python version if possible

Only use Python 3.9 if the Sphinx version requires it.

This requires setting the Python version requirement for Sphinx in
our pyproject.toml (see #359).

noxfile.py

@@ -30,18 +30,22 @@ def parametrize_dist():
     return nox.parametrize('dist', ['sdist', 'wheel'], ids=['sdist', 'wheel'])
 
 
-def parametrize(dependency, granularity='minor'):
-    return nox.parametrize(dependency, get_versions(dependency, granularity))
+def parametrize(dependency, granularity='minor', python=CURRENT_PYTHON):
+    versions = get_versions(dependency, granularity, python)
+    if python != CURRENT_PYTHON:
+        for version in get_versions(dependency, granularity, CURRENT_PYTHON):
+            versions.remove(version)
+    return nox.parametrize(dependency, versions)
 
 
 # sessions
 
-@nox_poetry.session()
+@nox_poetry.session
 def check(session):
     session.run('poetry', 'check', external=True)
 
 
-@nox_poetry.session()
+@nox_poetry.session
 def check_docs(session):
     _install(session, dependencies=['doc8', 'sphinx-immaterial',
                                     'sphinxcontrib-autoprogram'])
@@ -50,7 +54,7 @@ def check_docs(session):
     session.run('python', 'doc/build.py', 'doctest')
 
 
-@nox_poetry.session()
+@nox_poetry.session
 def build_docs(session):
     _install(session, dependencies=['Sphinx', 'sphinx-immaterial',
                                     'sphinxcontrib-autoprogram'])
@@ -70,30 +74,42 @@ def unit(session, dist):
     _unit(session, dist=dist)
 
 
-@nox_poetry.session(python='3.9')   # Sphinx >3.5 fail on 3.10
+@nox_poetry.session
 @parametrize('sphinx')
 def unit_sphinx(session, sphinx):
     _unit(session, sphinx=sphinx, ignore_deprecation_warnings=True)
 
 
+@nox_poetry.session(python='3.9')
+@parametrize('sphinx', python='3.9')
+def unit_sphinx_py39(session, sphinx):
+    _unit(session, sphinx=sphinx, ignore_deprecation_warnings=True)
+
+
 @nox_poetry.session(python=PYTHONS)
 @parametrize_dist()
 def regression(session, dist):
     _regression(session, dist=dist)
 
 
-@nox_poetry.session()
+@nox_poetry.session
 @parametrize('docutils')
 def regression_docutils(session, docutils):
     _regression(session, docutils=docutils, ignore_deprecation_warnings=True)
 
 
-@nox_poetry.session(python='3.9')   # Sphinx >3.5 fail on 3.10
+@nox_poetry.session
 @parametrize('sphinx')
 def regression_sphinx(session, sphinx):
     _regression(session, sphinx=sphinx, ignore_deprecation_warnings=True)
 
 
+@nox_poetry.session(python='3.9')
+@parametrize('sphinx', python='3.9')
+def regression_sphinx_py39(session, sphinx):
+    _regression(session, sphinx=sphinx, ignore_deprecation_warnings=True)
+
+
 # utility functions
 
 def _install(session, docutils=None, sphinx=None, dist='wheel',

noxutil.py

@@ -58,9 +58,8 @@ def allowed(version):
         python_version = parse_single_constraint(python)
         for requirement in requirements:
             python_versions = parse_single_constraint(requirement.python_versions)
-            if python_versions.allows(python_version) and requirement.constraint.allows(
-                version
-            ):
+            if (python_versions.allows(python_version)
+                    and requirement.constraint.allows(version)):
                 return True
         return False
 

pyproject.toml

@@ -93,7 +93,10 @@ rinoh-typeface-dejavuserif = "^0.1.3"
 rinoh-typeface-texgyrecursor = "^0.1.1"
 rinoh-typeface-texgyreheros = "^0.1.1"
 rinoh-typeface-texgyrepagella = "^0.1.1"
-Sphinx = { version = ">=2.2.1", optional = true }
+Sphinx = [
+  {version = ">=2.2.1", python = "<3.10", optional = true},
+  {version = ">=2.2.1,!=3.5.*,!=4.0.*,!=4.1.*", python = ">=3.10", optional = true}
+]
 
 [tool.poetry.group.dev.dependencies]
 doc8 = "^1.0.0"