Merge pull request #423 from devchat-ai/fix_test_error

Fix content concatenation in commit_cases.py

Author: yangbobo2021

test/workflows/commit_cases.py

@@ -157,7 +157,7 @@ def commit_message_compare(commit_message_a, commit_message_b, diff):
 
     content = ''
     for chunk in response:
-        content += chunk.choices[0].delta.content
+        content += (chunk.choices[0].delta.content or "")
     print('AI says:', content)
     return compare_result_parser(content)