diff --git a/test/threads/acb.dtd b/test/threads/acb.dtd
new file mode 100644
index 0000000..9fc77c5
--- /dev/null
+++ b/test/threads/acb.dtd
@@ -0,0 +1,7 @@
+<!ENTITY % a SYSTEM "http://example.org/a/a.dtd">
+%a;
+<!ENTITY % c SYSTEM "http://example.org/c/c.dtd">
+%c;
+<!ENTITY % b SYSTEM "http://example.org/b/b.dtd">
+%b;
+<!ELEMENT acb (a, c, b)>