fixtures: ensure cm fixtures don't finalize if never started

Author: delfick

README.rst

@@ -21,6 +21,10 @@ generator fixtures.
 Changelog
 ---------
 
+0.5.5 - TBD
+    * Fix bug where it was possible for an async generator fixture to
+      be cleaned up even if it was never started.
+
 0.5.4 - 26 January 2021
     * Added a ``--default-async-timeout`` option from the CLI. With many thanks
       to @andredias.

alt_pytest_asyncio/async_converters.py

@@ -189,6 +189,10 @@ def finalizer():
             """Yield again, to finalize."""
             __tracebackhide__ = True
 
+            nonlocal info
+            if "ran_once" not in info:
+                return
+
             info = {"gen_obj": gen_obj, "finalizer": True}
 
             async def async_finalizer():
@@ -242,3 +246,5 @@ def timeout_task(task):
         exc_info = sys.exc_info()
         e = exc_info[1]
         info["e"] = e
+    finally:
+        info["ran_once"] = True