[router] Add comprehensive E2E tests for Response API (#11988)

sgl-router/py_test/e2e_response_api/state_management.py

@@ -0,0 +1,135 @@
+"""
+State management tests for Response API.
+
+Tests both previous_response_id and conversation-based state management.
+These tests should work across all backends (OpenAI, XAI, gRPC).
+"""
+
+import unittest
+
+from base import ResponseAPIBaseTest
+
+
+class StateManagementTests(ResponseAPIBaseTest):
+    """Tests for state management using previous_response_id and conversation."""
+
+    def test_previous_response_id_chaining(self):
+        """Test chaining responses using previous_response_id."""
+        # First response
+        resp1 = self.create_response(
+            "My name is Alice and my friend is Bob. Remember it."
+        )
+        self.assertEqual(resp1.status_code, 200)
+        response1_id = resp1.json()["id"]
+
+        # Second response referencing first
+        resp2 = self.create_response(
+            "What is my name", previous_response_id=response1_id
+        )
+        self.assertEqual(resp2.status_code, 200)
+        response2_data = resp2.json()
+
+        # The model should remember the name from previous response
+        output_text = self._extract_output_text(response2_data)
+        self.assertIn("Alice", output_text)
+
+        # Third response referencing second
+        resp3 = self.create_response(
+            "What is my friend name?",
+            previous_response_id=response2_data["id"],
+        )
+        response3_data = resp3.json()
+        output_text = self._extract_output_text(response3_data)
+        self.assertEqual(resp3.status_code, 200)
+        self.assertIn("Bob", output_text)
+
+    @unittest.skip("TODO: Add the invalid previous_response_id check")
+    def test_previous_response_id_invalid(self):
+        """Test using invalid previous_response_id."""
+        resp = self.create_response(
+            "Test", previous_response_id="resp_invalid123", max_output_tokens=50
+        )
+        # Should return 404 or 400 for invalid response ID
+        if resp.status_code != 200:
+            print(f"\n❌ Response creation failed!")
+            print(f"Status: {resp.status_code}")
+            print(f"Response: {resp.text}")
+        self.assertIn(resp.status_code, [400, 404])
+
+    def test_conversation_with_multiple_turns(self):
+        """Test state management using conversation ID."""
+        # Create conversation
+        conv_resp = self.create_conversation(metadata={"topic": "math"})
+        self.assertEqual(conv_resp.status_code, 200)
+
+        conversation_id = conv_resp.json()["id"]
+
+        # First response in conversation
+        resp1 = self.create_response("I have 5 apples.", conversation=conversation_id)
+        self.assertEqual(resp1.status_code, 200)
+
+        # Second response in same conversation
+        resp2 = self.create_response(
+            "How many apples do I have?",
+            conversation=conversation_id,
+        )
+        self.assertEqual(resp2.status_code, 200)
+        output_text = self._extract_output_text(resp2.json())
+
+        # Should remember "5 apples"
+        self.assertTrue("5" in output_text or "five" in output_text.lower())
+
+        # Third response in same conversation
+        resp3 = self.create_response(
+            "If I get 3 more, how many total?",
+            conversation=conversation_id,
+        )
+        self.assertEqual(resp3.status_code, 200)
+        output_text = self._extract_output_text(resp3.json())
+
+        # Should calculate 5 + 3 = 8
+        self.assertTrue("8" in output_text or "eight" in output_text.lower())
+        list_resp = self.list_conversation_items(conversation_id)
+        self.assertEqual(list_resp.status_code, 200)
+        items = list_resp.json()["data"]
+        # Should have at least 6 items (3 inputs + 3 outputs)
+        self.assertGreaterEqual(len(items), 6)
+
+    def test_mutually_exclusive_parameters(self):
+        """Test that previous_response_id and conversation are mutually exclusive."""
+        # Create conversation and response
+        conv_resp = self.create_conversation()
+        conversation_id = conv_resp.json()["id"]
+
+        resp1 = self.create_response("Test")
+        response1_id = resp1.json()["id"]
+
+        # Try to use both parameters
+        resp = self.create_response(
+            "This should fail",
+            previous_response_id=response1_id,
+            conversation=conversation_id,
+        )
+
+        # Should return 400 Bad Request
+        self.assertEqual(resp.status_code, 400)
+        error_data = resp.json()
+        self.assertIn("error", error_data)
+        self.assertIn("mutually exclusive", error_data["error"]["message"].lower())
+
+    # Helper methods
+
+    def _extract_output_text(self, response_data: dict) -> str:
+        """Extract text content from response output."""
+        output = response_data.get("output", [])
+        if not output:
+            return ""
+
+        text_parts = []
+        for item in output:
+            content = item.get("content", [])
+            for part in content:
+                if part.get("type") == "output_text":
+                    text_parts.append(part.get("text", ""))
+
+        return " ".join(text_parts)