diff --git a/src/testdir/test_options.vim b/src/testdir/test_options.vim
index 21dd7fe..dee435c 100644
--- a/src/testdir/test_options.vim
+++ b/src/testdir/test_options.vim
@@ -48,3 +48,52 @@
   endif
 endfunc
 
+func Test_filetype_valid()
+  set ft=valid_name
+  call assert_equal("valid_name", &filetype)
+  set ft=valid-name
+  call assert_equal("valid-name", &filetype)
+
+  call assert_fails(":set ft=wrong;name", "E474:")
+  call assert_fails(":set ft=wrong\\\\name", "E474:")
+  call assert_fails(":set ft=wrong\\|name", "E474:")
+  call assert_fails(":set ft=wrong/name", "E474:")
+  call assert_fails(":set ft=wrong\\\nname", "E474:")
+  call assert_equal("valid-name", &filetype)
+
+  exe "set ft=trunc\x00name"
+  call assert_equal("trunc", &filetype)
+endfunc
+
+func Test_syntax_valid()
+  set syn=valid_name
+  call assert_equal("valid_name", &syntax)
+  set syn=valid-name
+  call assert_equal("valid-name", &syntax)
+
+  call assert_fails(":set syn=wrong;name", "E474:")
+  call assert_fails(":set syn=wrong\\\\name", "E474:")
+  call assert_fails(":set syn=wrong\\|name", "E474:")
+  call assert_fails(":set syn=wrong/name", "E474:")
+  call assert_fails(":set syn=wrong\\\nname", "E474:")
+  call assert_equal("valid-name", &syntax)
+
+  exe "set syn=trunc\x00name"
+  call assert_equal("trunc", &syntax)
+endfunc
+
+func Test_keymap_valid()
+  call assert_fails(":set kmp=valid_name", "E544:")
+  call assert_fails(":set kmp=valid_name", "valid_name")
+  call assert_fails(":set kmp=valid-name", "E544:")
+  call assert_fails(":set kmp=valid-name", "valid-name")
+
+  call assert_fails(":set kmp=wrong;name", "E474:")
+  call assert_fails(":set kmp=wrong\\\\name", "E474:")
+  call assert_fails(":set kmp=wrong\\|name", "E474:")
+  call assert_fails(":set kmp=wrong/name", "E474:")
+  call assert_fails(":set kmp=wrong\\\nname", "E474:")
+
+  call assert_fails(":set kmp=trunc\x00name", "E544:")
+  call assert_fails(":set kmp=trunc\x00name", "trunc")
+endfunc