Treat Python warnings as errors during testing

tests/test_ext_napoleon_iterators.py

@@ -3,8 +3,13 @@
 import sys
 from unittest import TestCase
 
+import pytest
+
 from sphinx.deprecation import RemovedInSphinx70Warning
-from sphinx.ext.napoleon.iterators import modify_iter, peek_iter
+
+with pytest.warns(DeprecationWarning,
+                  match="sphinx.ext.napoleon.iterators is deprecated."):
+    from sphinx.ext.napoleon.iterators import modify_iter, peek_iter
 
 
 class ModuleIsDeprecatedTest(TestCase):

tests/test_setup_command.py

@@ -33,7 +33,7 @@ def setup_command(request, tempdir, rootdir):
 
         proc = subprocess.Popen(
             command,
-            env=dict(os.environ, PYTHONPATH=pythonpath),
+            env=dict(os.environ, PYTHONPATH=pythonpath, PYTHONWARNINGS='default'),
             stdout=subprocess.PIPE,
             stderr=subprocess.PIPE)
         yield namedtuple('setup', 'pkgroot,proc')(pkgrootdir, proc)