Use pytest directly in tox and relax version pins

pyproject.toml

@@ -49,8 +49,8 @@ test = [
   "importlib-metadata<5.0",
 
   # Pytest for running the tests.
-  "pytest>=7.0.1,<10",
-  "pytest-cov>=4.0.0,<8.0",
+  "pytest==9.*",
+  "pytest-cov==7.*",
   "pytest-django>=4.5.2,<5",
 
   # Remove when dropping support for Django<5.0

tox.ini

@@ -10,11 +10,7 @@ envlist =
        docs
 
 [testenv]
-commands =
-    python -W error::DeprecationWarning \
-           -W "ignore:'cgi' is deprecated:DeprecationWarning" \
-           -W error::PendingDeprecationWarning \
-           runtests.py --coverage {posargs}
+commands = pytest --cov --cov-report xml {posargs}
 envdir = {toxworkdir}/venvs/{envname}
 setenv =
        PYTHONDONTWRITEBYTECODE=1