test: config cap under aiohttp's 4 MB frame; own marker id for the upload test

A 4 MB cap could never be reported: the frame limit rejects the message first
and the socket closes with 1009, so the user gets a dropped connection instead
of 'too_large'. 2 MB is ~30x a real three-floor configuration (70 KB measured).

The upload test listed a folder test_ha_upload.py also writes into.

custom_components/houseplan/validation.py

@@ -81,10 +81,12 @@ MAX_KNOWN_DEVICES = 20000
 MAX_TEXT = 500          # names, models, ids
 MAX_DESCRIPTION = 4000
 MAX_URL = 2000
-# Below the WebSocket frame limit on purpose: a payload larger than that never
-# reaches the handler at all — the socket closes with 1009 and the user sees a
-# dropped connection instead of an error they can act on.
-MAX_CONFIG_BYTES = 4 * 1024 * 1024
+# Comfortably below the WebSocket frame limit (aiohttp's default is 4 MB): a
+# payload larger than the frame never reaches the handler at all — the socket
+# closes with 1009 and the user sees a dropped connection instead of an error
+# they can act on. For scale, a real three-floor home with ~200 devices stores
+# about 70 KB, so this is ~30x headroom.
+MAX_CONFIG_BYTES = 2 * 1024 * 1024
 
 _TEXT = vol.All(str, vol.Length(max=MAX_TEXT))
 _TEXT_OR_NONE = vol.Any(None, _TEXT)

tests_backend/test_ha_websocket.py

@@ -681,12 +681,12 @@ async def test_upload_never_overwrites_an_existing_attachment(
         assert resp.status == 200, await resp.text()
         return (await resp.json())["url"]
 
-    first = await upload("m1", "manual.pdf", b"ONE")
-    second = await upload("m1", "manual.pdf", b"TWO")
+    first = await upload("m9", "manual.pdf", b"ONE")
+    second = await upload("m9", "manual.pdf", b"TWO")
     assert first != second, "the second upload must not take the first name"
 
-    folder = os.path.join(hass.config.path(FILES_DIR), "m1")
-    # the HA test config dir is shared across the module — look only at ours
+    folder = os.path.join(hass.config.path(FILES_DIR), "m9")
+    # the HA test config dir is shared across the module — hence our own marker id
     names = sorted(
         n for n in await hass.async_add_executor_job(os.listdir, folder) if n.startswith("manual")
     )