patch 8.2.0509: various code is not properly tested.

Problem:    various code is not properly tested.
Solution:   Add more tests. (Yegappan Lakshmanan, closes #5871)
diff --git a/src/testdir/test_options.vim b/src/testdir/test_options.vim
index f5e0e9b..f111894 100644
--- a/src/testdir/test_options.vim
+++ b/src/testdir/test_options.vim
@@ -1,6 +1,7 @@
 " Test for options
 
 source check.vim
+source view_util.vim
 
 func Test_whichwrap()
   set whichwrap=b,s
@@ -707,4 +708,12 @@
   set rightleft&
 endfunc
 
+" Test for the "debug" option
+func Test_debug_option()
+  set debug=beep
+  exe "normal \<C-c>"
+  call assert_equal('Beep!', Screenline(&lines))
+  set debug&
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab