diff --git a/tests/fixtures/aws.py b/tests/fixtures/aws.py
index 7eea4bd..9fb3345 100644
--- a/tests/fixtures/aws.py
+++ b/tests/fixtures/aws.py
@@ -1,15 +1,17 @@
 import boto3
-from moto import mock_s3
 import pytest
 
+try:
+    # Moto 4.x
+    from moto import mock_s3
+except ImportError:
+    # Moto 5.x
+    from moto import mock_aws as mock_s3
 
 @pytest.fixture
 def aws_session():
-    mock_s3_server = mock_s3()
-    mock_s3_server.start()
-    yield boto3.Session()
-    mock_s3_server.stop()
-
+    with mock_s3():
+        yield boto3.Session()
 
 @pytest.fixture
 def aws_s3_bucket(aws_session):