From f2416507f020996509ccfd83d05a12c3dfc57a37 Mon Sep 17 00:00:00 2001
From: Noah Stapp <noah.stapp@mongodb.com>
Date: Mon, 23 Feb 2026 14:17:47 -0500
Subject: [PATCH] Fix test

---
 pymongo/asynchronous/mongo_client.py | 11 +++++------
 pymongo/synchronous/mongo_client.py  | 11 +++++------
 test/asynchronous/test_session.py    |  2 ++
 test/test_session.py                 |  2 ++
 4 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/pymongo/asynchronous/mongo_client.py b/pymongo/asynchronous/mongo_client.py
index afd634a76..d70186586 100644
--- a/pymongo/asynchronous/mongo_client.py
+++ b/pymongo/asynchronous/mongo_client.py
@@ -2268,15 +2268,14 @@ class AsyncMongoClient(common.BaseObject, Generic[_DocumentType]):
         self, session: Optional[client_session.AsyncClientSession]
     ) -> AsyncGenerator[Optional[client_session.AsyncClientSession], None]:
         """If provided session is None, lend a temporary session."""
+        if session is not None and not isinstance(session, client_session.AsyncClientSession):
+            raise ValueError(
+                f"'session' argument must be an AsyncClientSession or None, not {type(session)}"
+            )
 
         # Check for a bound session. If one exists, treat it as an explicitly passed session.
         session = session or self._get_bound_session()
-
-        if session is not None:
-            if not isinstance(session, client_session.AsyncClientSession):
-                raise ValueError(
-                    f"'session' argument must be an AsyncClientSession or None, not {type(session)}"
-                )
+        if session:
             # Don't call end_session.
             yield session
             return
diff --git a/pymongo/synchronous/mongo_client.py b/pymongo/synchronous/mongo_client.py
index 863bce5be..943cd1f5b 100644
--- a/pymongo/synchronous/mongo_client.py
+++ b/pymongo/synchronous/mongo_client.py
@@ -2264,15 +2264,14 @@ class MongoClient(common.BaseObject, Generic[_DocumentType]):
         self, session: Optional[client_session.ClientSession]
     ) -> Generator[Optional[client_session.ClientSession], None]:
         """If provided session is None, lend a temporary session."""
+        if session is not None and not isinstance(session, client_session.ClientSession):
+            raise ValueError(
+                f"'session' argument must be a ClientSession or None, not {type(session)}"
+            )
 
         # Check for a bound session. If one exists, treat it as an explicitly passed session.
         session = session or self._get_bound_session()
-
-        if session is not None:
-            if not isinstance(session, client_session.ClientSession):
-                raise ValueError(
-                    f"'session' argument must be a ClientSession or None, not {type(session)}"
-                )
+        if session:
             # Don't call end_session.
             yield session
             return
diff --git a/test/asynchronous/test_session.py b/test/asynchronous/test_session.py
index 1f1412b58..3ef2f7337 100644
--- a/test/asynchronous/test_session.py
+++ b/test/asynchronous/test_session.py
@@ -877,6 +877,8 @@ class TestSession(AsyncIntegrationTest):
 
         session1 = self.client.start_session()
         session2 = self.client.start_session()
+        session1._materialize()
+        session2._materialize()
         try:
             self.listener.reset()
             # Uses implicit session
diff --git a/test/test_session.py b/test/test_session.py
index 61bf4ef37..4c5859693 100644
--- a/test/test_session.py
+++ b/test/test_session.py
@@ -877,6 +877,8 @@ class TestSession(IntegrationTest):
 
         session1 = self.client.start_session()
         session2 = self.client.start_session()
+        session1._materialize()
+        session2._materialize()
         try:
             self.listener.reset()
             # Uses implicit session