diff --git a/docs/test_cases.md b/docs/test_cases.md
index 6e436e39..2c027fe4 100644
--- a/docs/test_cases.md
+++ b/docs/test_cases.md
@@ -16,6 +16,7 @@
  * [t00015](./test_cases/t00015.md) - Namespace fun
  * [t00016](./test_cases/t00016.md) - Unnamed enums and empty templates
  * [t00017](./test_cases/t00017.md) - Test include relations also as members flag
+ * [t00018](./test_cases/t00018.md) - Pimpl pattern
 ## Sequence diagrams
  * [t20001](./test_cases/t20001.md) - Basic sequence diagram
 ## Configuration diagrams