a2a-loopback-tests

Skill: A2A Loopback Tests

Use this skill in test-author mode when writing integration tests that exercise multiple agents without Docker.

The fixture

# tests/integration/conftest.py
import httpx
import pytest
from httpx import ASGITransport
from agent_framework.testing import MockChatClient

from src.agents.inventory.server import app as inventory_app
from src.agents.supplier.server import app as supplier_app
# ...orchestrator etc.


@pytest.fixture
async def fleet(monkeypatch):
    # 1. Patch GitHubCopilotAgent at every agent's import site so the
    #    real SDK / bundled Node CLI never starts.
    fake = MockChatClient()  # exposes async .run(message) -> AgentResponse[None]
    for mod in (
        "src.agents.inventory.agent",
        "src.agents.supplier.agent",
        "src.agents.logistics.agent",
        "src.agents.pricing.agent",
        "src.agents.orchestrator.agent",
    ):
        monkeypatch.setattr(f"{mod}.GitHubCopilotAgent", lambda **_: fake)

    # 2. Mount each FastAPI app behind ASGITransport.
    clients = {
        "inventory": httpx.AsyncClient(transport=ASGITransport(app=inventory_app),
                                       base_url="http://inventory"),
        # ... etc
    }
    yield clients
    for c in clients.values():
        await c.aclose()

Rules

1. Never import GitHubCopilotAgent directly in a test — always patch its import site so the real SDK / Node CLI never runs.
2. Never start a real network server (no uvicorn.run). ASGITransport only.
3. Do not patch MCPStreamableHTTPTool — it is not used in this repo. MCP wiring lives inside GitHubCopilotOptions(mcp_servers={...}); the agent is already mocked at step 1, so MCP is short-circuited automatically.
4. Assert structure (response.json()["tool_calls"]) and keyword presence ("store-101" in response.json()["output"]). No exact string equality.
5. Mark every test pytest.mark.asyncio (or rely on asyncio_mode = "auto" in pyproject.toml).