Update PYTHONWARNINGS on tox.ini to reduce meaningless warnings

tests/conftest.py

@@ -35,14 +35,6 @@ def pytest_report_header(config):
         sys.version.split()[0])
 
 
-def _filter_warnings():
-    def ignore(**kwargs): warnings.filterwarnings('ignore', **kwargs)
-
-    ignore(category=DeprecationWarning, module='site')  # virtualenv
-    ignore(category=PendingDeprecationWarning, module=r'_pytest\..*')
-    ignore(category=ImportWarning, module='pkgutil')
-
-
 def _initialize_test_directory(session):
     testroot = os.path.join(str(session.config.rootdir), 'tests')
     tempdir = os.path.abspath(os.getenv('SPHINX_TEST_TEMPDIR',
@@ -58,5 +50,4 @@ def _initialize_test_directory(session):
 
 
 def pytest_sessionstart(session):
-    _filter_warnings()
     _initialize_test_directory(session)

tox.ini

@@ -21,7 +21,7 @@ deps =
     du13: docutils==0.13.1
     du14: docutils==0.14
 setenv =
-    PYTHONWARNINGS = all,ignore::ImportWarning:pkgutil
+    PYTHONWARNINGS = all,ignore::ImportWarning:pkgutil,ignore::ImportWarning:importlib._bootstrap,ignore::ImportWarning:importlib._bootstrap_external,ignore::ImportWarning:pytest_cov.plugin,ignore::DeprecationWarning:site,ignore::DeprecationWarning:_pytest.assertion.rewrite,ignore::DeprecationWarning:_pytest.fixtures
     SPHINX_TEST_TEMPDIR = {envdir}/testbuild
 commands=
     pytest -Wall --durations 25 {posargs}