old_contents: from AlphaTwirl.Events import BEvents as Events
  from AlphaTwirl.Events import Branch
  import unittest
  import ROOT
  
  ##____________________________________________________________________________||
  inputPath = '/Users/sakuma/work/cms/c150130_RA1_data/c150130_01_PHYS14/20150331_SingleMu/TTJets/treeProducerSusyAlphaT/tree.root'
  treeName = 'tree'
  
  ##____________________________________________________________________________||
  @unittest.skip("skip TestBEventsWithFile")
  class TestBEventsWithFile(unittest.TestCase):
  
      def test_branch(self):
          inputFile = ROOT.TFile.Open(inputPath)
          tree = inputFile.Get(treeName)
          events = Events(tree)
  
          jet_pt = events.jet_pt
          met_pt = events.met_pt
          self.assertIsInstance(jet_pt, Branch)
          self.assertIsInstance(met_pt, Branch)
  
          self.assertEqual(0, len(jet_pt))
          self.assertEqual(1, len(met_pt))
          self.assertEqual(0.0, met_pt[0])
  
          tree.GetEntry(0)
          self.assertEqual(2, len(jet_pt))
          self.assertEqual(1, len(met_pt))
          self.assertEqual(124.55626678466797, jet_pt[0])
          self.assertEqual(86.90544128417969, jet_pt[1])
          self.assertAlmostEqual(43.783382415771484, met_pt[0])
  
          tree.GetEntry(1)
          self.assertEqual(3, len(jet_pt))
          self.assertEqual(1, len(met_pt))
          self.assertEqual(112.48554992675781, jet_pt[0])
          self.assertEqual(52.32780075073242, jet_pt[1])
          self.assertEqual(48.861289978027344, jet_pt[2])
          self.assertAlmostEqual(20.483951568603516, met_pt[0])
  
  ##____________________________________________________________________________||
  
new_contents: from AlphaTwirl.Events import BEvents as Events
  from AlphaTwirl.Events import Branch
  import unittest
  
  ##____________________________________________________________________________||
  hasROOT = False
  try:
      import ROOT
      hasROOT = True
  except ImportError:
      pass
  
  ##____________________________________________________________________________||
  inputPath = '/Users/sakuma/work/cms/c150130_RA1_data/c150130_01_PHYS14/20150331_SingleMu/TTJets/treeProducerSusyAlphaT/tree.root'
  treeName = 'tree'
  
  ##____________________________________________________________________________||
  @unittest.skipUnless(hasROOT, "has no ROOT")
  @unittest.skip("skip TestBEventsWithFile")
  class TestBEventsWithFile(unittest.TestCase):
  
      def test_branch(self):
          inputFile = ROOT.TFile.Open(inputPath)
          tree = inputFile.Get(treeName)
          events = Events(tree)
  
          jet_pt = events.jet_pt
          met_pt = events.met_pt
          self.assertIsInstance(jet_pt, Branch)
          self.assertIsInstance(met_pt, Branch)
  
          self.assertEqual(0, len(jet_pt))
          self.assertEqual(1, len(met_pt))
          self.assertEqual(0.0, met_pt[0])
  
          tree.GetEntry(0)
          self.assertEqual(2, len(jet_pt))
          self.assertEqual(1, len(met_pt))
          self.assertEqual(124.55626678466797, jet_pt[0])
          self.assertEqual(86.90544128417969, jet_pt[1])
          self.assertAlmostEqual(43.783382415771484, met_pt[0])
  
          tree.GetEntry(1)
          self.assertEqual(3, len(jet_pt))
          self.assertEqual(1, len(met_pt))
          self.assertEqual(112.48554992675781, jet_pt[0])
          self.assertEqual(52.32780075073242, jet_pt[1])
          self.assertEqual(48.861289978027344, jet_pt[2])
          self.assertAlmostEqual(20.483951568603516, met_pt[0])
  
  ##____________________________________________________________________________||
  
subject: check if ROOT exists in test_BEventsWithFile.py