Skip incomplete L2 error test for now

Python/poiseuille/test_poiseuille_l2.py

@@ -14,10 +14,7 @@ from vtk_utilities import vertical_column_from_mesh, get_values_from_indices
 class TestPoiseuilleFlow(unittest.TestCase):
 
     def test_poiseuille_flow(self):
-        """
-        WHEN comparing the simulation results to the analytical solution THEN the L2-Norm should be less than 1e-4
-        """
-        # self.skipTest("Skipping test! This test is not implemented correctly")
+        self.skipTest("Skipping test! This test has not been implemented correctly yet")
         plt.ion()
 
         channel_height = 10