headroom/tests/test_proxy_gemini_integration.py
Ben Younes 9fde127534
fix(proxy): relocate stray system-role messages to the top-level system param (#765) (#1357)
## Description

On requests large enough to trigger compression, the proxy emitted an
upstream Anthropic request whose `messages[0]` had `role: "system"`.
Anthropic's Messages API rejects any `system` role inside `messages[]`:

```
400 invalid_request_error: "messages.0: use the top-level 'system' parameter for the initial system prompt"
```

The original request correctly carries its system prompt in the
top-level `system` parameter; a compression/transform/pipeline step
relocates the harness system block into `messages[0]`, so the request
fails outright (intermittent only because it requires a context large
enough to compress).

This adds a wire-contract guard in the Anthropic forwarder: as the
**last** step before sending upstream (after every transform, memory
injection, tool sort, and pipeline extension, covering both the Bedrock
and direct paths), any stray `role="system"` message is relocated out of
`messages[]` and merged back into the top-level `system` parameter.
Content order is preserved (existing system first, relocated content
after) and block-level `cache_control` survives. The guard is a no-op on
the common path (no system-role entry → inputs pass through unchanged).

Closes #765

## Type of Change

- [x] Bug fix (non-breaking change that fixes an issue)
- [ ] New feature (non-breaking change that adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
- [ ] Performance improvement
- [ ] Code refactoring (no functional changes)

## Changes Made

- `headroom/proxy/helpers.py`: new pure helper
`relocate_system_messages_to_top_level(messages, system) ->
(clean_messages, new_system, changed)` plus `_system_message_to_blocks`.
Handles `system` being `None`/`str`/`list`, never drops content,
preserves order and content blocks.
- `headroom/proxy/handlers/anthropic.py`: invoke the guard just before
the byte-faithful forward block; on relocation, update
`body["messages"]`/`body["system"]`, mark the body mutated
(`system_role_relocated`) so the byte-faithful forwarder re-serializes,
and log a warning.
- `tests/test_proxy_handler_helpers.py`: 3 unit tests (relocate stray
system into top-level, append-to-existing-system order, no-op without a
system entry).
- `CHANGELOG.md`: Bug Fixes entry.

## Testing

- [x] Unit tests pass (`pytest`)
- [x] Linting passes (`ruff check .`)
- [x] Type checking passes (`mypy headroom`)
- [x] New tests added for new functionality
- [x] Manual testing performed

### Test Output

```text
$ uv run --extra dev python -m pytest tests/test_proxy_handler_helpers.py -q
29 passed in 4.95s

# Regression on the forward path (byte-faithful forwarding, system-prompt immutability, cache stability):
$ uv run --extra dev python -m pytest tests/test_proxy_handler_helpers.py tests/test_proxy_byte_faithful_forwarding.py tests/test_proxy_system_prompt_immutable.py tests/test_proxy_anthropic_cache_stability.py -q
90 passed, 15 warnings in 29.72s

$ uv run ruff check headroom/proxy/helpers.py headroom/proxy/handlers/anthropic.py tests/test_proxy_handler_helpers.py
All checks passed!

$ uv run ruff format --check ...   # 3 files already formatted
$ uv run mypy headroom/proxy/helpers.py headroom/proxy/handlers/anthropic.py
Success: no issues found in 2 source files
```

## Test verification (RED → GREEN)

The new tests exercise the guard directly and import the new helper at
module top, so reverting the production fix makes them fail at
collection.

**RED — production fix reverted (helper removed):**
```text
ImportError while importing test module 'tests/test_proxy_handler_helpers.py'.
E   ImportError: cannot import name 'relocate_system_messages_to_top_level' from 'headroom.proxy.helpers'
=========================== 1 error in 0.41s ===============================
```

**GREEN — production fix applied:**
```text
tests/test_proxy_handler_helpers.py ...                                  [100%]
======================= 3 passed, 26 deselected in 1.50s =======================
```

## Real Behavior Proof

- Environment: Python 3.13, `uv run` in this repo, branch
`fix/issue-765`.
- Exact command / steps: ran the guard on a body in the exact #765
failure shape — `system: None` and a `role="system"` harness block at
`messages[0]`:
- Observed result:
  ```text
  BEFORE: messages[0].role = system (Anthropic 400 trigger)
  changed       = True
  AFTER roles   = ['user', 'assistant']
system param = [{"type": "text", "text": "You are Claude Code.
<system-reminder>...</system-reminder>"}]
OK: no role=system in messages[]; system content preserved in top-level
param
  ```
The illegal `role="system"` entry is removed from `messages[]` and its
content lands in the top-level `system` parameter — exactly the body
Anthropic accepts.
- Not tested: a full live 250k+-token Claude Code session against the
real Anthropic API (needs a large live context + API key); the fix is
validated at the request-shaping boundary the 400 is raised on.

## Review Readiness

- [x] I have performed a self-review
- [x] This PR is ready for human review

## Checklist

- [x] My code follows the project's style guidelines
- [x] I have performed a self-review of my code
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [x] I have updated the CHANGELOG.md if applicable

## Additional Notes

The guard intentionally fires at the forwarder boundary rather than in
any single transform: the issue's captures show the relocation can
originate from the compression path, and pipeline extensions / hooks can
also mutate `messages` late. Enforcing Anthropic's wire contract once,
at the point the body is serialized upstream, fixes the 400 regardless
of which step introduced the stray entry and matches the architecture
invariant "never produce a `system`-role entry within `messages[]`".

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: JerrettDavis <mxjerrett@gmail.com>
2026-08-13 11:52:09 -05:00

262 lines
9.2 KiB
Python

"""Integration tests for the proxy with real Gemini API calls.
These tests require a valid GEMINI_API_KEY environment variable.
They test the actual /v1/chat/completions endpoint with real API calls.
Run with:
GEMINI_API_KEY=your-key pytest tests/test_proxy_gemini_integration.py -v
"""
import json
import os
import pytest
# Skip entire module if no API key
pytestmark = pytest.mark.skipif(
not os.environ.get("GEMINI_API_KEY"), reason="GEMINI_API_KEY not set"
)
pytest.importorskip("fastapi")
pytest.importorskip("httpx")
from fastapi.testclient import TestClient # noqa: E402
from headroom.proxy.server import ProxyConfig, create_app # noqa: E402
from tests._gemini_live import skip_if_gemini_quota_exhausted # noqa: E402
GEMINI_BASE_URL = "https://generativelanguage.googleapis.com/v1beta/openai"
@pytest.fixture
def gemini_client():
"""Create test client configured to forward to Gemini."""
config = ProxyConfig(
optimize=False,
cache_enabled=False,
rate_limit_enabled=False,
cost_tracking_enabled=False,
openai_api_url=GEMINI_BASE_URL,
)
app = create_app(config)
with TestClient(app) as client:
yield client
@pytest.fixture
def api_key():
"""Get Gemini API key from environment."""
return os.environ.get("GEMINI_API_KEY")
class TestGeminiChatCompletions:
"""Test /v1/chat/completions with real Gemini API."""
def test_basic_completion(self, gemini_client, api_key):
"""Basic chat completion works."""
response = gemini_client.post(
"/v1/chat/completions",
headers={"Authorization": f"Bearer {api_key}"},
json={
"model": "gemini-2.0-flash",
"messages": [
{"role": "user", "content": "What is 2+2? Reply with just the number."}
],
},
)
skip_if_gemini_quota_exhausted(response)
assert response.status_code == 200
data = response.json()
# Verify OpenAI-compatible response format
assert "choices" in data
assert len(data["choices"]) > 0
assert "message" in data["choices"][0]
assert "content" in data["choices"][0]["message"]
assert "4" in data["choices"][0]["message"]["content"]
# Verify usage stats
assert "usage" in data
assert "prompt_tokens" in data["usage"]
assert "completion_tokens" in data["usage"]
def test_multi_turn_conversation(self, gemini_client, api_key):
"""Multi-turn conversations maintain context."""
response = gemini_client.post(
"/v1/chat/completions",
headers={"Authorization": f"Bearer {api_key}"},
json={
"model": "gemini-2.0-flash",
"messages": [
{"role": "system", "content": "You are a helpful assistant. Be concise."},
{"role": "user", "content": "My name is TestUser123."},
{"role": "assistant", "content": "Nice to meet you, TestUser123!"},
{"role": "user", "content": "What is my name?"},
],
},
)
skip_if_gemini_quota_exhausted(response)
assert response.status_code == 200
data = response.json()
content = data["choices"][0]["message"]["content"].lower()
assert "testuser123" in content
def test_streaming(self, gemini_client, api_key):
"""Streaming responses work correctly."""
response = gemini_client.post(
"/v1/chat/completions",
headers={"Authorization": f"Bearer {api_key}"},
json={
"model": "gemini-2.0-flash",
"stream": True,
"messages": [{"role": "user", "content": "Count from 1 to 3."}],
},
)
skip_if_gemini_quota_exhausted(response)
assert response.status_code == 200
# Parse SSE stream
chunks = []
for line in response.text.strip().split("\n"):
if line.startswith("data: ") and line != "data: [DONE]":
chunk = json.loads(line[6:])
chunks.append(chunk)
assert len(chunks) > 0
# Verify chunk format
for chunk in chunks:
assert "choices" in chunk
assert "delta" in chunk["choices"][0]
assert chunk["object"] == "chat.completion.chunk"
def test_function_calling(self, gemini_client, api_key):
"""Function calling / tools work correctly."""
response = gemini_client.post(
"/v1/chat/completions",
headers={"Authorization": f"Bearer {api_key}"},
json={
"model": "gemini-2.0-flash",
"messages": [{"role": "user", "content": "What is the weather in Paris?"}],
"tools": [
{
"type": "function",
"function": {
"name": "get_weather",
"description": "Get the weather for a location",
"parameters": {
"type": "object",
"properties": {
"location": {"type": "string", "description": "City name"}
},
"required": ["location"],
},
},
}
],
"tool_choice": "auto",
},
)
skip_if_gemini_quota_exhausted(response)
assert response.status_code == 200
data = response.json()
# Verify tool call response
message = data["choices"][0]["message"]
assert "tool_calls" in message
assert len(message["tool_calls"]) > 0
tool_call = message["tool_calls"][0]
assert tool_call["function"]["name"] == "get_weather"
assert "paris" in tool_call["function"]["arguments"].lower()
def test_json_mode(self, gemini_client, api_key):
"""JSON response format works."""
response = gemini_client.post(
"/v1/chat/completions",
headers={"Authorization": f"Bearer {api_key}"},
json={
"model": "gemini-2.0-flash",
"messages": [
{
"role": "user",
"content": "Return a JSON object with keys 'name' and 'age' for a person named Alice who is 30 years old.",
}
],
"response_format": {"type": "json_object"},
},
)
skip_if_gemini_quota_exhausted(response)
assert response.status_code == 200
data = response.json()
content = data["choices"][0]["message"]["content"]
# Parse the response as JSON
parsed = json.loads(content)
assert "name" in parsed or "Name" in parsed
assert "age" in parsed or "Age" in parsed
class TestGeminiModels:
"""Test /v1/models endpoint with Gemini."""
def test_list_models(self, gemini_client, api_key):
"""Can list available models."""
response = gemini_client.get("/v1/models", headers={"Authorization": f"Bearer {api_key}"})
skip_if_gemini_quota_exhausted(response)
# This goes through passthrough handler
assert response.status_code == 200
data = response.json()
assert "data" in data or "object" in data
class TestProxyStats:
"""Test that proxy stats track Gemini requests correctly."""
def test_stats_track_requests(self, gemini_client, api_key):
"""Proxy stats track Gemini requests."""
# Make a request
response = gemini_client.post(
"/v1/chat/completions",
headers={"Authorization": f"Bearer {api_key}"},
json={"model": "gemini-2.0-flash", "messages": [{"role": "user", "content": "Hi"}]},
)
skip_if_gemini_quota_exhausted(response)
# Check stats
stats_response = gemini_client.get("/stats")
assert stats_response.status_code == 200
stats = stats_response.json()
assert stats["requests"]["total"] >= 1
assert stats["requests"]["by_provider"]["openai"] >= 1
assert "gemini" in str(stats["requests"]["by_model"]).lower()
class TestErrorHandling:
"""Test error handling with Gemini."""
def test_invalid_api_key(self, gemini_client):
"""Invalid API key returns appropriate error."""
response = gemini_client.post(
"/v1/chat/completions",
headers={"Authorization": "Bearer invalid-key-123"},
json={"model": "gemini-2.0-flash", "messages": [{"role": "user", "content": "Hi"}]},
)
# Should return 4xx error
assert response.status_code >= 400
def test_invalid_model(self, gemini_client, api_key):
"""Invalid model returns appropriate error."""
response = gemini_client.post(
"/v1/chat/completions",
headers={"Authorization": f"Bearer {api_key}"},
json={
"model": "nonexistent-model-xyz",
"messages": [{"role": "user", "content": "Hi"}],
},
)
# Should return 4xx error
assert response.status_code >= 400