diff --git a/test/strscan/test_stringscanner.rb b/test/strscan/test_stringscanner.rb
index ae05254d49fd7b..7eea0cd49120c8 100644
--- a/test/strscan/test_stringscanner.rb
+++ b/test/strscan/test_stringscanner.rb
@@ -905,7 +905,7 @@ def test_scan_integer
     assert_predicate s, :matched?
 
     s = create_string_scanner('-123abc')
-    assert_equal -123, s.scan_integer
+    assert_equal(-123, s.scan_integer)
     assert_equal 4, s.pos
     assert_predicate s, :matched?