diff --git a/test/porousmediumflow/richards/implicit/lens/main.cc b/test/porousmediumflow/richards/implicit/lens/main.cc
index c68cde825420d9dab854dfb27c54bf8b6b32be99..e8246fbd4596e1800b64d2d8a6b2ead466562fcb 100644
--- a/test/porousmediumflow/richards/implicit/lens/main.cc
+++ b/test/porousmediumflow/richards/implicit/lens/main.cc
@@ -50,6 +50,10 @@
 
 #include "problem.hh"
 
+#ifndef DIFFMETHOD
+#define DIFFMETHOD DiffMethod::numeric
+#endif
+
 ////////////////////////
 // the main function
 ////////////////////////