UX-15: mutations fail named checks, not crashes

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

goodwe_controller/test_setup_only.py

@@ -339,10 +339,14 @@ class Session:
 
 
 def _refused(coro):
+    """True only for the read-only refusal; a request that reached the
+    session (AssertionError there) or no refusal at all is False."""
     try:
         asyncio.run(coro)
     except H.ReadOnly:
         return True
+    except Exception:                                   # noqa: BLE001
+        return False
     return False
 
 
@@ -372,8 +376,10 @@ check("control: a normal HomeAssistant does send the write", _sent
 try:
     M.Controller(dict(_ok), _ro, None, None, stop=asyncio.Event())
     _built = True
-except ValueError:
-    _built = False
+except ValueError as err:
+    _built = "read-only" not in str(err)
+except Exception:                                       # noqa: BLE001
+    _built = True           # it got past the check and failed on something else
 check("no controller can be built on a read-only HomeAssistant", not _built)
 try:
     setuponly.SetupOnly(SHIPPED, _rw, None)