diff --git a/runtime/syntax/testdir/input/c.c b/runtime/syntax/testdir/input/c.c
index c96fb33..ede2caf 100644
--- a/runtime/syntax/testdir/input/c.c
+++ b/runtime/syntax/testdir/input/c.c
@@ -1,4 +1,5 @@
 /* vi:set ts=8 sts=4 sw=4 noet:
+ * TEST_SETUP let g:c_comment_strings = 1
  *
  * VIM - Vi IMproved	by Bram Moolenaar
  *
diff --git a/runtime/syntax/testdir/input/markdown_conceal.markdown b/runtime/syntax/testdir/input/markdown_conceal.markdown
new file mode 100644
index 0000000..8049d68
--- /dev/null
+++ b/runtime/syntax/testdir/input/markdown_conceal.markdown
@@ -0,0 +1,15 @@
+_Italic_, *Italic*.  __Bold__, **Bold**.  
+___Bold Italic___, ***Bold Italic***.  
+~~Strikethrough~~, S̶t̶r̶i̶k̶e̶t̶h̶r̶o̶u̶g̶h̶.
+
+~~~html
+<p>
+<del>Strikethrough</del>, <s>Strikethrough</s>.<br />
+~~~
+
+```html
+<strong><em>Bold Italic</em></strong>.
+<strong><em>Bold Italic</em></strong>.<br />
+<strong>Bold</strong>, <strong>Bold</strong>.
+<em>Italic</em>, <em>Italic</em>.
+```
diff --git a/runtime/syntax/testdir/input/setup/markdown_conceal.vim b/runtime/syntax/testdir/input/setup/markdown_conceal.vim
new file mode 100644
index 0000000..a1585b1
--- /dev/null
+++ b/runtime/syntax/testdir/input/setup/markdown_conceal.vim
@@ -0,0 +1,8 @@
+if has('conceal')
+	let g:markdown_syntax_conceal = 1
+	setlocal conceallevel=3 concealcursor=n
+endif
+
+let g:markdown_fenced_languages = ['html']
+highlight link markdownBold Todo
+highlight link htmlBold Todo