diff --git a/src/testdir/test_diffmode.vim b/src/testdir/test_diffmode.vim
index 088ec5c..3625a68 100644
--- a/src/testdir/test_diffmode.vim
+++ b/src/testdir/test_diffmode.vim
@@ -280,13 +280,13 @@
   set diffopt=icase,foldcolumn:0
 
   e one
-  call setline(1, ['One', 'Two', 'Three', 'Four'])
+  call setline(1, ['One', 'Two', 'Three', 'Four', 'Fi#ve'])
   redraw
   let normattr = screenattr(1, 1)
   diffthis
 
   botright vert new two
-  call setline(1, ['one', 'TWO', 'Three ', 'Four'])
+  call setline(1, ['one', 'TWO', 'Three ', 'Four', 'fI=VE'])
   diffthis
 
   redraw
@@ -295,6 +295,10 @@
   call assert_notequal(normattr, screenattr(3, 1))
   call assert_equal(normattr, screenattr(4, 1))
 
+  let dtextattr = screenattr(5, 3)
+  call assert_notequal(dtextattr, screenattr(5, 1))
+  call assert_notequal(dtextattr, screenattr(5, 5))
+
   diffoff!
   %bwipe!
   set diffopt&