diff --git a/tests/__init__.py b/tests/__init__.py
index b4f509dda7..cb3d054cbb 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -18,7 +18,8 @@
 
 from googleapiclient import _helpers as util
 
-
-def setup_package():
-    """Run on testing package."""
-    util.positional_parameters_enforcement = "EXCEPTION"
+# The test suite is written against strict positional parameter enforcement:
+# violations must raise TypeError rather than only log a warning. This used to
+# be configured in a nose-era setup_package() hook, which pytest never calls,
+# so set it at import time instead.
+util.positional_parameters_enforcement = util.POSITIONAL_EXCEPTION
diff --git a/tests/test__helpers.py b/tests/test__helpers.py
index 56df6f8807..4322d623c7 100644
--- a/tests/test__helpers.py
+++ b/tests/test__helpers.py
@@ -22,6 +22,14 @@
 
 
 class PositionalTests(unittest.TestCase):
+    def setUp(self):
+        # These tests mutate the module-level enforcement setting; restore it
+        # so the rest of the suite keeps running in strict mode.
+        saved_enforcement = _helpers.positional_parameters_enforcement
+        self.addCleanup(
+            setattr, _helpers, "positional_parameters_enforcement", saved_enforcement
+        )
+
     def test_usage(self):
         _helpers.positional_parameters_enforcement = _helpers.POSITIONAL_EXCEPTION