Add multierror cancellation tests

tests/test_cancellation.py

@@ -14,22 +14,36 @@ async def assert_err():
     assert 0
 
 
-def test_remote_error(arb_addr):
+@pytest.mark.parametrize(
-    """Verify an error raises in a subactor is propagated to the parent.
+    'args_err',
+    [
+        # expected to be thrown in assert_err
+        ({}, AssertionError),
+        # argument mismatch raised in _invoke()
+        ({'unexpected': 10}, TypeError)
+    ],
+    ids=['no_args', 'unexpected_args'],
+)
+def test_remote_error(arb_addr, args_err):
+    """Verify an error raised in a subactor that is propagated
+    to the parent nursery, contains underlying builtin erorr type
+    infot and causes cancellation and reraising.
     """
+    args, errtype = args_err
+
     async def main():
         async with tractor.open_nursery() as nursery:
 
-            portal = await nursery.run_in_actor('errorer', assert_err)
+            portal = await nursery.run_in_actor('errorer', assert_err, **args)
 
             # get result(s) from main task
             try:
-                return await portal.result()
+                await portal.result()
-            except tractor.RemoteActorError:
+            except tractor.RemoteActorError as err:
+                assert err.type == errtype
                 print("Look Maa that actor failed hard, hehh")
                 raise
-            except Exception:
+            else:
-                pass
                 assert 0, "Remote error was not raised?"
 
     with pytest.raises(tractor.RemoteActorError):
@@ -37,14 +51,42 @@ def test_remote_error(arb_addr):
         tractor.run(main, arbiter_addr=arb_addr)
 
 
+def test_multierror(arb_addr):
+    """Verify we raise a ``trio.MultiError`` out of a nursery where
+    more then one actor errors.
+    """
+    async def main():
+        async with tractor.open_nursery() as nursery:
+
+            await nursery.run_in_actor('errorer1', assert_err)
+            portal2 = await nursery.run_in_actor('errorer2', assert_err)
+
+            # get result(s) from main task
+            try:
+                await portal2.result()
+            except tractor.RemoteActorError as err:
+                assert err.type == AssertionError
+                print("Look Maa that first actor failed hard, hehh")
+                raise
+
+        # here we should get a `trio.MultiError` containing exceptions
+        # from both subactors
+
+    with pytest.raises(trio.MultiError):
+        tractor.run(main, arbiter_addr=arb_addr)
+
+
 def do_nothing():
     pass
 
 
 def test_cancel_single_subactor(arb_addr):
-
+    """Ensure a ``ActorNursery.start_actor()`` spawned subactor
-    async def main():
+    cancels when the nursery is cancelled.
-
+    """
+    async def spawn_actor():
+        """Spawn an actor that blocks indefinitely.
+        """
         async with tractor.open_nursery() as nursery:
 
             portal = await nursery.start_actor(
@@ -55,7 +97,7 @@ def test_cancel_single_subactor(arb_addr):
             # would hang otherwise
             await nursery.cancel()
 
-    tractor.run(main, arbiter_addr=arb_addr)
+    tractor.run(spawn_actor, arbiter_addr=arb_addr)
 
 
 async def stream_forever():
@@ -87,13 +129,22 @@ async def test_cancel_infinite_streamer():
     assert n.cancelled
 
 
+@pytest.mark.parametrize(
+    'num_actors_and_errs',
+    [
+        (1, tractor.RemoteActorError, AssertionError),
+        (2, tractor.MultiError, AssertionError)
+    ],
+    ids=['one_actor', 'two_actors'],
+)
 @tractor_test
-async def test_one_cancels_all():
+async def test_some_cancels_all(num_actors_and_errs):
     """Verify one failed actor causes all others in the nursery
     to be cancelled just like in trio.
 
     This is the first and only supervisory strategy at the moment.
     """
+    num, first_err, err_type = num_actors_and_errs
     try:
         async with tractor.open_nursery() as n:
             real_actors = []
@@ -103,13 +154,21 @@ async def test_one_cancels_all():
                     rpc_module_paths=[__name__],
                 ))
 
+            for i in range(num):
                 # start one actor that will fail immediately
-            await n.run_in_actor('extra', assert_err)
+                await n.run_in_actor(f'extra_{i}', assert_err)
 
-        # should error here with a ``RemoteActorError`` containing
+        # should error here with a ``RemoteActorError`` or
-        # an ``AssertionError`
+        # ``MultiError`` containing an ``AssertionError`
+
+    except first_err as err:
+        if isinstance(err, trio.MultiError):
+            assert len(err.exceptions) == num
+            for exc in err.exceptions:
+                assert exc.type == err_type
+        else:
+            assert err.type == err_type
 
-    except tractor.RemoteActorError:
         assert n.cancelled is True
         assert not n._children
     else: