diff --git a/src/testdir/test_diffmode.vim b/src/testdir/test_diffmode.vim
index aae8b36..027cdc8 100644
--- a/src/testdir/test_diffmode.vim
+++ b/src/testdir/test_diffmode.vim
@@ -668,13 +668,13 @@
   diffthis
   redraw
 
-  call assert_equal(synIDattr(diff_hlID(-1, 1), "name"), "")
+  call diff_hlID(-1, 1)->synIDattr("name")->assert_equal("")
 
-  call assert_equal(synIDattr(diff_hlID(1, 1), "name"), "DiffChange")
-  call assert_equal(synIDattr(diff_hlID(1, 2), "name"), "DiffText")
-  call assert_equal(synIDattr(diff_hlID(2, 1), "name"), "")
-  call assert_equal(synIDattr(diff_hlID(3, 1), "name"), "DiffAdd")
-  call assert_equal(synIDattr(diff_hlID(4, 1), "name"), "")
+  call diff_hlID(1, 1)->synIDattr("name")->assert_equal("DiffChange")
+  call diff_hlID(1, 2)->synIDattr("name")->assert_equal("DiffText")
+  call diff_hlID(2, 1)->synIDattr("name")->assert_equal("")
+  call diff_hlID(3, 1)->synIDattr("name")->assert_equal("DiffAdd")
+  call diff_hlID(4, 1)->synIDattr("name")->assert_equal("")
 
   wincmd w
   call assert_equal(synIDattr(diff_hlID(1, 1), "name"), "DiffChange")