PYTHON-5409 Make test_implicit_sessions_checkout less flaky (#2366)

Author: ShaneHarvey

test/asynchronous/test_session.py

@@ -194,10 +194,11 @@ async def test_implicit_sessions_checkout(self):
         # successful connection checkout" test from Driver Sessions Spec.
         succeeded = False
         lsid_set = set()
-        failures = 0
-        for _ in range(5):
-            listener = OvertCommandListener()
-            client = await self.async_rs_or_single_client(event_listeners=[listener], maxPoolSize=1)
+        listener = OvertCommandListener()
+        client = await self.async_rs_or_single_client(event_listeners=[listener], maxPoolSize=1)
+        # Retry up to 10 times because there is a known race that can cause multiple
+        # sessions to be used: connection check in happens before session check in
+        for _ in range(10):
             cursor = client.db.test.find({})
             ops: List[Tuple[Callable, List[Any]]] = [
                 (client.db.test.find_one, [{"_id": 1}]),
@@ -240,9 +241,9 @@ async def target(op, *args):
                 if i.command.get("lsid"):
                     lsid_set.add(i.command.get("lsid")["id"])
             if len(lsid_set) == 1:
+                # Break on first success.
                 succeeded = True
-            else:
-                failures += 1
+                break
         self.assertTrue(succeeded, lsid_set)
 
     async def test_pool_lifo(self):

test/test_session.py

@@ -194,10 +194,11 @@ def test_implicit_sessions_checkout(self):
         # successful connection checkout" test from Driver Sessions Spec.
         succeeded = False
         lsid_set = set()
-        failures = 0
-        for _ in range(5):
-            listener = OvertCommandListener()
-            client = self.rs_or_single_client(event_listeners=[listener], maxPoolSize=1)
+        listener = OvertCommandListener()
+        client = self.rs_or_single_client(event_listeners=[listener], maxPoolSize=1)
+        # Retry up to 10 times because there is a known race that can cause multiple
+        # sessions to be used: connection check in happens before session check in
+        for _ in range(10):
             cursor = client.db.test.find({})
             ops: List[Tuple[Callable, List[Any]]] = [
                 (client.db.test.find_one, [{"_id": 1}]),
@@ -240,9 +241,9 @@ def target(op, *args):
                 if i.command.get("lsid"):
                     lsid_set.add(i.command.get("lsid")["id"])
             if len(lsid_set) == 1:
+                # Break on first success.
                 succeeded = True
-            else:
-                failures += 1
+                break
         self.assertTrue(succeeded, lsid_set)
 
     def test_pool_lifo(self):