gh-136285: Improve pickle protocol testing in test_interpreters

Author: sobolevn

Lib/test/test_interpreters/test_api.py

@@ -412,9 +412,11 @@ def test_equality(self):
 
     def test_pickle(self):
         interp = interpreters.create()
-        data = pickle.dumps(interp)
-        unpickled = pickle.loads(data)
-        self.assertEqual(unpickled, interp)
+        for protocol in range(2, pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(protocol=protocol):
+                data = pickle.dumps(interp, protocol)
+                unpickled = pickle.loads(data)
+                self.assertEqual(unpickled, interp)
 
 
 class TestInterpreterIsRunning(TestBase):

Lib/test/test_interpreters/test_channels.py

@@ -121,9 +121,11 @@ def test_equality(self):
 
     def test_pickle(self):
         ch, _ = channels.create()
-        data = pickle.dumps(ch)
-        unpickled = pickle.loads(data)
-        self.assertEqual(unpickled, ch)
+        for protocol in range(2, pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(protocol=protocol):
+                data = pickle.dumps(ch, protocol)
+                unpickled = pickle.loads(data)
+                self.assertEqual(unpickled, ch)
 
 
 class TestSendChannelAttrs(TestBase):
@@ -152,9 +154,11 @@ def test_equality(self):
 
     def test_pickle(self):
         _, ch = channels.create()
-        data = pickle.dumps(ch)
-        unpickled = pickle.loads(data)
-        self.assertEqual(unpickled, ch)
+        for protocol in range(2, pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(protocol=protocol):
+                data = pickle.dumps(ch, protocol)
+                unpickled = pickle.loads(data)
+                self.assertEqual(unpickled, ch)
 
 
 class TestSendRecv(TestBase):

Lib/test/test_interpreters/test_queues.py

@@ -188,9 +188,11 @@ def test_equality(self):
 
     def test_pickle(self):
         queue = queues.create()
-        data = pickle.dumps(queue)
-        unpickled = pickle.loads(data)
-        self.assertEqual(unpickled, queue)
+        for protocol in range(2, pickle.HIGHEST_PROTOCOL + 1):
+            with self.subTest(protocol=protocol):
+                data = pickle.dumps(queue, protocol)
+                unpickled = pickle.loads(data)
+                self.assertEqual(unpickled, queue)
 
 
 class TestQueueOps(TestBase):