display informations in browser when there is an ImportError

product/ERP5Type/Tool/ClassTool.py

@@ -1239,12 +1239,15 @@ def initialize( context ):
         global global_stream
         global_stream = StringIO()
         from Products.ERP5Type.tests.ERP5TypeLiveTestCase import runLiveTest
+        try:
           result = runLiveTest(test_list,
                               run_only=run_only,
                               debug=debug,
                               path=path,
                               stream=global_stream,
                               verbosity=verbosity)
+        except ImportError:
+          traceback.print_exc(file=global_stream)
         global_stream.seek(0)
         return global_stream.read()