bpo-23819: Replace AssertionError with proper excs

Author: kumaraditya303

Lib/asyncio/events.py

@@ -101,7 +101,8 @@ class TimerHandle(Handle):
     __slots__ = ['_scheduled', '_when']
 
     def __init__(self, when, callback, args, loop, context=None):
-        assert when is not None
+        if when is None:
+            raise ValueError('when cannot be None')
         super().__init__(callback, args, loop, context)
         if self._source_traceback:
             del self._source_traceback[-1]
@@ -661,7 +662,8 @@ def get_event_loop(self):
     def set_event_loop(self, loop):
         """Set the event loop."""
         self._local._set_called = True
-        assert loop is None or isinstance(loop, AbstractEventLoop)
+        if loop is not None and not isinstance(loop, AbstractEventLoop):
+            raise TypeError(f'loop must be an instance of AbstractEventLoop or None, not {type(loop)}')
         self._local._loop = loop
 
     def new_event_loop(self):
@@ -745,7 +747,8 @@ def set_event_loop_policy(policy):
 
     If policy is None, the default policy is restored."""
     global _event_loop_policy
-    assert policy is None or isinstance(policy, AbstractEventLoopPolicy)
+    if policy is not None and not isinstance(policy, AbstractEventLoopPolicy):
+        raise TypeError(f'policy must be an instance of AbstractEventLoopPolicy or None, not {type(policy)}')
     _event_loop_policy = policy
 
 

Lib/test/test_asyncio/test_events.py

@@ -2323,7 +2323,7 @@ def callback(*args):
         self.assertIsNone(h._args)
 
         # when cannot be None
-        self.assertRaises(AssertionError,
+        self.assertRaises(ValueError,
                           asyncio.TimerHandle, None, callback, args,
                           self.loop)
 
@@ -2592,7 +2592,7 @@ def test_set_event_loop(self):
         policy = asyncio.DefaultEventLoopPolicy()
         old_loop = policy.get_event_loop()
 
-        self.assertRaises(AssertionError, policy.set_event_loop, object())
+        self.assertRaises(TypeError, policy.set_event_loop, object())
 
         loop = policy.new_event_loop()
         policy.set_event_loop(loop)
@@ -2608,7 +2608,7 @@ def test_get_event_loop_policy(self):
 
     def test_set_event_loop_policy(self):
         self.assertRaises(
-            AssertionError, asyncio.set_event_loop_policy, object())
+            TypeError, asyncio.set_event_loop_policy, object())
 
         old_policy = asyncio.get_event_loop_policy()