should be it

external/duckdb/test/sql/function/generic/test_set.test

@@ -0,0 +1,66 @@
+# name: test/sql/function/generic/test_set.test
+# description: Test SET function
+# group: [generic]
+
+# unrecognized configuration parameter
+statement error
+SELECT CURRENT_SETTING('a');
+----
+
+statement error
+SELECT CURRENT_SETTING('memori_limit');
+----
+
+statement ok
+SELECT CURRENT_SETTING('default_null_order');
+
+statement ok
+SET default_null_order = 'nulls_last';
+
+# set from a function
+statement ok
+SET default_null_order = concat('nulls', '_', 'last');
+
+query I
+SELECT CURRENT_SETTING('default_null_order');
+----
+NULLS_LAST
+
+query I
+SELECT CURRENT_SETTING('DEFAULT_NULL_ORDER');
+----
+NULLS_LAST
+
+query I
+SELECT * FROM range(3) UNION ALL SELECT NULL ORDER BY 1
+----
+0
+1
+2
+NULL
+
+statement error
+SELECT CURRENT_SETTING(i::VARCHAR) FROM range(1) tbl(i)
+----
+
+statement error
+SELECT CURRENT_SETTING(NULL)
+----
+
+statement error
+SELECT CURRENT_SETTING(CAST(NULL AS TEXT))
+----
+
+statement error
+SELECT CURRENT_SETTING('')
+----
+
+statement error
+SET default_null_order = colref || '_last';
+----
+cannot contain column names
+
+statement error
+SET default_null_order = (SELECT 'nulls_last')
+----
+cannot contain subqueries