fixing test for damper

Author: aoeftiger

PyHEADTAIL/feedback/transverse_damper.py

@@ -26,13 +26,16 @@ def __init__(self, dampingrate_x, dampingrate_y, *args, **kwargs):
             self.prints('Damper in Y active')
         elif not dampingrate_x and not dampingrate_y:
             self.prints('Dampers not active')
-            self.track = lambda x: 0
         else:
             self.gain_x = 2/dampingrate_x
             self.gain_y = 2/dampingrate_y
             self.track = self.track_all
             self.prints('Dampers active')
 
+    # will be overwritten at initialisation
+    def track(self, beam):
+        pass
+
     def track_horizontal(self, beam):
         beam.xp -= self.gain_x * beam.mean_xp()
 

PyHEADTAIL/testing/unittests/test_gpu_interface.py

@@ -296,7 +296,7 @@ def test_transverse_damper(self):
         bunch_gpu = self.create_all1_bunch()
         dampingrate_x = 0.01
         dampingrate_y =  0.05
-        damp = TransverseDamper(dampingrate_x, dampingrate_y)
+        damp = TransverseDamper(dampingrate_x, dampingrate_y, printer=SilentPrinter())
         self.assertTrue(self._track_cpu_gpu([damp], bunch_cpu, bunch_gpu),
             'Tracking TransverseDamper CPU/GPU differs')