diff --git a/src/testdir/test_syntax.vim b/src/testdir/test_syntax.vim
index 49f8833..d152ec5 100644
--- a/src/testdir/test_syntax.vim
+++ b/src/testdir/test_syntax.vim
@@ -631,6 +631,7 @@
 
 " Check highlighting for a small piece of C code with a screen dump.
 func Test_syntax_c()
+  CheckScreendump
   CheckRunVimInTerminal
   call writefile([
 	\ '/* comment line at the top */',