diff --git a/src/MGmolInterface.h b/src/MGmolInterface.h
index 9a9bf8a6..ec913944 100644
--- a/src/MGmolInterface.h
+++ b/src/MGmolInterface.h
@@ -25,6 +25,7 @@ class MGmolInterface
     virtual int setupConstraintsFromInput(const std::string input_file) = 0;
     virtual void setup()                                                = 0;
     virtual void run()                                                  = 0;
+    virtual void cleanup()                                              = 0;
 
     virtual double evaluateEnergyAndForces(const std::vector<double>& tau,
         const std::vector<short>& atnumbers, std::vector<double>& forces)
diff --git a/tests/WFEnergyAndForces/testWFEnergyAndForces.cc b/tests/WFEnergyAndForces/testWFEnergyAndForces.cc
index c9e28d48..64765c7a 100644
--- a/tests/WFEnergyAndForces/testWFEnergyAndForces.cc
+++ b/tests/WFEnergyAndForces/testWFEnergyAndForces.cc
@@ -190,6 +190,7 @@ int main(int argc, char** argv)
             }
         }
 
+        mgmol->cleanup();
         delete mgmol;
 
     } // close main scope