Say that acquire raises on a malformed lease

autoform_cli/claims.py

@@ -390,7 +390,10 @@ def expired(cls, lease: Mapping[str, Any], now: float | None = None) -> bool:
         return expires_at <= comparison_time
 
     def acquire(self, key: str, ttl: int | float = CLAIM_TTL_S, steal: bool = False, note: str = "") -> bool:
-        """CAS-acquire a free, expired, malformed, owned, or explicitly stolen lease."""
+        """CAS-acquire a free, expired, owned, or explicitly stolen lease.
+
+        A malformed lease raises ``MalformedLeaseError``, even with ``steal``.
+        """
         key = _validate_key(key)
         _validate_ttl(ttl)
         self._ensure_scratch()

tests/test_claims.py

@@ -255,6 +255,7 @@ def test_malformed_lease_is_unverifiable_and_not_takeover_eligible(tmp_path: Pat
         lambda: board.renew("malformed"),
         lambda: board.release("malformed"),
         lambda: board.acquire("malformed", ttl=600),
+        lambda: board.acquire("malformed", ttl=600, steal=True),
     ):
         with pytest.raises(claims.MalformedLeaseError):
             operation()