Improve nest SDM integration error handling (#43271)

tests/components/nest/conftest.py

@@ -0,0 +1,57 @@
+"""Common libraries for test setup."""
+
+import aiohttp
+from google_nest_sdm.auth import AbstractAuth
+import pytest
+
+
+class FakeAuth(AbstractAuth):
+    """A fake implementation of the auth class that records requests.
+
+    This class captures the outgoing requests, and can also be used by
+    tests to set up fake responses.  This class is registered as a response
+    handler for a fake aiohttp_server and can simulate successes or failures
+    from the API.
+    """
+
+    # Tests can set fake responses here.
+    responses = []
+    # The last request is recorded here.
+    method = None
+    url = None
+    json = None
+
+    # Set up by fixture
+    client = None
+
+    def __init__(self):
+        """Initialize FakeAuth."""
+        super().__init__(None, None)
+
+    async def async_get_access_token(self) -> str:
+        """Return a valid access token."""
+        return ""
+
+    async def request(self, method, url, json):
+        """Capure the request arguments for tests to assert on."""
+        self.method = method
+        self.url = url
+        self.json = json
+        return await self.client.get("/")
+
+    async def response_handler(self, request):
+        """Handle fake responess for aiohttp_server."""
+        if len(self.responses) > 0:
+            return self.responses.pop(0)
+        return aiohttp.web.json_response()
+
+
+@pytest.fixture
+async def auth(aiohttp_client):
+    """Fixture for an AbstractAuth."""
+    auth = FakeAuth()
+    app = aiohttp.web.Application()
+    app.router.add_get("/", auth.response_handler)
+    app.router.add_post("/", auth.response_handler)
+    auth.client = await aiohttp_client(app)
+    return auth