Update

dune/pdelab-systemtesting/poisson/CMakeLists.txt

 add_dune_system_test(BASENAME poisson
                      INIFILE poisson.mini
                      SOURCE poisson_uniform.cc
-                     SCRIPT ${DUNE_TESTTOOLS_PATH}/python/wrapper/vtkcompare.py)
+                     SCRIPT vtkcompare.py)
 
 add_dune_system_test(BASENAME poisson
                      INIFILE poisson_conv.mini
                      SOURCE poisson_uniform.cc
-                     SCRIPT ${DUNE_TESTTOOLS_PATH}/python/wrapper/convergencetest.py)
+                     SCRIPT convergencetest.py)
+
+add_dune_system_test(BASENAME poisson
+                     INIFILE poisson_parallel.mini
+                     SOURCE poisson_uniform.cc
+                     SCRIPT execute_parallel.py)