enable curio in pytest; add special handling for curio scopes; add te…

…st to test whether callbacks may kill themselves during transitions

tests/conftest.py

@@ -14,7 +14,7 @@
 @pytest.fixture(params=[
     pytest.param('asyncio'),
     pytest.param('trio'),
-    # pytest.param('curio'),
+    pytest.param('curio'),
 ])
 def anyio_backend(request):
     return request.param

tests/test_transitions_anyio.py

@@ -143,6 +143,21 @@ def sync_callback(event_data):
     assert m.is_B() is True
 
 
+async def test_async_callback_trigger(machine_cls):
+    mock_processed = MagicMock()
+
+    async def on_event(event_data):
+        await event_data.model.to_C()
+        mock_processed()
+
+    m = machine_cls(states=['A', 'B', 'C'],
+                    transitions=[dict(trigger='go', source='A', dest='B', after=on_event)],
+                    initial='A', send_event=True)
+    await m.go()
+    assert m.is_C()
+    assert mock_processed.called
+
+
 async def test_async_invalid_triggers(m):
     await m.to_B()
 

transitions_anyio/__init__.py

@@ -1,4 +1,5 @@
 from anyio import create_task_group, get_cancelled_exc_class, open_cancel_scope
+from anyio._backends._curio import CancelScope as CurioCancelScope
 from transitions.extensions import GraphMachine
 from transitions.extensions.asyncio import (AsyncMachine, AsyncTransition,
                                             HierarchicalAsyncMachine,
@@ -21,7 +22,8 @@ async def with_result(func):
         return results
 
     async def process_context(self, func, model):
-        if self.current_context.get() is None:
+        current = self.current_context.get()
+        if current is None or isinstance(current, CurioCancelScope):
             res = False
             async with open_cancel_scope() as scope:
                 self.current_context.set(scope)