diff --git a/src/testdir/runtest.vim b/src/testdir/runtest.vim
index f03fe44..b1ffd19 100644
--- a/src/testdir/runtest.vim
+++ b/src/testdir/runtest.vim
@@ -180,6 +180,7 @@
 
 
 " Prepare for calling test_garbagecollect_now().
+" Also avois some delays in Insert mode completion.
 let v:testing = 1
 
 " By default, copy each buffer line into allocated memory, so that valgrind can