diff --git a/TurTLE/test/collisions/stokes_rhs.hpp b/TurTLE/test/collisions/stokes_rhs.hpp
index 582f7089f3ed0759329b172363ac14823e500fdd..41268149f23f590bc1e6bb9f9ce011aba5c34c8c 100644
--- a/TurTLE/test/collisions/stokes_rhs.hpp
+++ b/TurTLE/test/collisions/stokes_rhs.hpp
@@ -43,7 +43,7 @@ class stokes_rhs: public abstract_particle_rhs
     public:
         stokes_rhs(){}
         ~stokes_rhs(){}
-        const int getStateSize() const
+        int getStateSize() const
         {
              // 3 numbers for position
              // // 9 numbers for components of deformation tensor                                                                                                                                                        // 3 numbers to store logarithmic factors