diff --git a/tests/python/test_list_all_modules.py b/tests/python/test_list_all_modules.py
index 2cbdb5e..ab78d56 100644
--- a/tests/python/test_list_all_modules.py
+++ b/tests/python/test_list_all_modules.py
@@ -267,7 +267,13 @@ def test_builtins_still_discoverable_under_only_c(self):
         # Regression guard: a builtin IS a C module (compiled into the interpreter) but has no
         # filename, so routing the seed through the file-based only-c check would drop every
         # builtin from --only-c runs.
-        self.assertIn("math", self._discovered(set(), only_c=True))
+        #
+        # Which modules are built in is a property of the BUILD, not of fusil: `math` is
+        # compiled into the interpreters used here but is a shared extension on the
+        # python.org builds CI installs, where naming it made this fail on every run since
+        # 2026-08-19. Assert the invariant over whatever this interpreter actually has.
+        expected = set(sys.builtin_module_names) - {"__main__"}
+        self.assertEqual(self._discovered(set(), only_c=True) & expected, expected)
 
     def test_dunder_main_still_excluded(self):
         self.assertNotIn("__main__", self._discovered(set()))
diff --git a/tests/python/test_target_py311_compat.py b/tests/python/test_target_py311_compat.py
index 25a319d..00d98ea 100644
--- a/tests/python/test_target_py311_compat.py
+++ b/tests/python/test_target_py311_compat.py
@@ -38,9 +38,14 @@ def test_tricky_objects_runs_without_types_CapsuleType(self):
         # killing the session during the prelude -- before a single call is fuzzed.
         source = (SAMPLES / "tricky_objects.py").read_text()
 
+        # `__getattr__` must be skipped as well, not just CapsuleType. CPython 3.13 defines
+        # CapsuleType LAZILY through a module-level __getattr__ (PEP 562); copying that into
+        # the shim resolves the attribute straight back to the real module and the shim stops
+        # shimming. 3.14 defines it eagerly via _types, which is why this passed locally and
+        # failed on CI's 3.13 job on every run since 2026-08-19.
         shim = types.ModuleType("types")
         for name in dir(types):
-            if name != "CapsuleType":
+            if name not in ("CapsuleType", "__getattr__"):
                 setattr(shim, name, getattr(types, name))
         self.assertFalse(hasattr(shim, "CapsuleType"))