diff --git a/src/testdir/view_util.vim b/src/testdir/view_util.vim
index d9e740d..71cb071 100644
--- a/src/testdir/view_util.vim
+++ b/src/testdir/view_util.vim
@@ -51,6 +51,7 @@
   return attrs
 endfunc
 
+" Create a new window with the requested size and fix it.
 func NewWindow(height, width) abort
   exe a:height . 'new'
   exe a:width . 'vsp'