(test) add blocking callback test

litellm/tests/test_async_callbacks.py

@@ -0,0 +1,49 @@
+import json
+import sys
+import os
+import io, asyncio
+
+import logging
+
+logging.basicConfig(level=logging.DEBUG)
+sys.path.insert(0, os.path.abspath("../.."))
+
+from litellm import completion
+import litellm
+
+litellm.num_retries = 3
+import time
+import pytest
+
+
+async def custom_callback(
+    kwargs,  # kwargs to completion
+    completion_response,  # response from completion
+    start_time,
+    end_time,  # start/end time
+):
+    # Your custom code here
+    print("LITELLM: in custom callback function")
+    print("kwargs", kwargs)
+    print("completion_response", completion_response)
+    print("start_time", start_time)
+    print("end_time", end_time)
+    time.sleep(1)
+
+    return
+
+
+def test_time_to_run_10_completions():
+    litellm.callbacks = [custom_callback]
+    start = time.time()
+
+    asyncio.run(
+        litellm.acompletion(
+            model="gpt-3.5-turbo", messages=[{"role": "user", "content": "hello"}]
+        )
+    )
+    end = time.time()
+    print(f"Time to run 10 completions: {end - start}")
+
+
+test_time_to_run_10_completions()