Validate scope in Session.wait_for_schema_agreement

The docstring promised ValueError for an invalid scope, but no check
existed: an unknown value silently fell through to cluster-wide
behaviour. Coerce/validate the argument against SchemaAgreementScope up
front (also accepting the plain string values) and raise a clear
ValueError listing the valid scopes.

Author: sylwiaszunejko

cassandra/cluster.py

@@ -3482,6 +3482,14 @@ def wait_for_schema_agreement(self, wait_time: Optional[float] = None,
         if wait_time is not None and wait_time <= 0:
             raise ValueError("wait_time must be greater than 0")
 
+        try:
+            scope = SchemaAgreementScope(scope)
+        except ValueError:
+            raise ValueError(
+                "scope must be one of %s" % (
+                    [s.value for s in SchemaAgreementScope],)
+            )
+
         total_timeout = wait_time if wait_time is not None else self.cluster.max_schema_agreement_wait
         if total_timeout <= 0:
             raise ValueError("total_timeout must be greater than 0")
@@ -5325,7 +5333,7 @@ def _execute_after_prepare(self, host, connection, pool, response):
                     new_metadata_id = response.result_metadata_id
                     if new_metadata_id is not None:
                         self.prepared_statement.result_metadata_id = new_metadata_id
-                
+
                 # use self._query to re-use the same host and
                 # at the same time properly borrow the connection
                 if pool is None and connection is not None and connection.is_control_connection: