diff --git a/src/testdir/test_blob.vim b/src/testdir/test_blob.vim
index a8d8da0..b41ca78 100644
--- a/src/testdir/test_blob.vim
+++ b/src/testdir/test_blob.vim
@@ -363,7 +363,7 @@
       VAR b = 0z0011
       call add("", 0x01)
   END
-  call CheckLegacyAndVim9Failure(lines, ['E897:', 'E1013:', 'E1211:'])
+  call CheckLegacyAndVim9Failure(lines, ['E897:', 'E1013:', 'E1226:'])
 
   let lines =<< trim END
       add(test_null_blob(), 0x22)