Return HTTP 400 for streaming validation errors (#21900)

test/registered/openai_server/validation/test_request_length_validation.py

@@ -67,6 +67,23 @@ class TestRequestLengthValidation(CustomTestCase):
 
         self.assertIn("is longer than the model's context length", str(cm.exception))
 
+    def test_input_length_longer_than_context_length_streaming(self):
+        client = openai.Client(api_key=self.api_key, base_url=f"{self.base_url}/v1")
+
+        long_text = "hello " * 1200
+
+        with self.assertRaises(openai.BadRequestError) as cm:
+            client.chat.completions.create(
+                model=DEFAULT_SMALL_MODEL_NAME_FOR_TEST,
+                messages=[
+                    {"role": "user", "content": long_text},
+                ],
+                temperature=0,
+                stream=True,
+            )
+
+        self.assertIn("is longer than the model's context length", str(cm.exception))
+
     def test_max_tokens_validation(self):
         client = openai.Client(api_key=self.api_key, base_url=f"{self.base_url}/v1")