diff --git a/tests/unit-tests/security/transform.t.cpp b/tests/unit-tests/security/transform.t.cpp
index ea2fa0f..f0a6b27 100644
--- a/tests/unit-tests/security/transform.t.cpp
+++ b/tests/unit-tests/security/transform.t.cpp
@@ -58,6 +58,9 @@
 
   transform::Base64Decode* base64Decode = nullptr;
   BOOST_CHECK(base64Decode == nullptr);
+
+  transform::DigestFilter* digestFilter = nullptr;
+  BOOST_CHECK(digestFilter == nullptr);
 }
 
 BOOST_AUTO_TEST_SUITE_END() // TestTransform