old_contents: from __future__ import print_function, division, absolute_import
  from fontTools.misc.py23 import *
  from fontTools.varLib.featureVars import (
      overlayFeatureVariations)
  
  
  def test_explosion(n = 10):
      conds = []
      for i in range(n):
          end = i / n
          start = end - 1.
          region = [{'axis': (start, end)}]
          subst = {'g%.2g'%start: 'g%.2g'%end}
          conds.append((region, subst))
      overlaps = overlayFeatureVariations(conds)
      # XXX Currently fails for n > 2!
      #assert len(overlaps) == 2 * n - 1, overlaps
      return conds, overlaps
  
  if __name__ == "__main__":
      import sys
      from pprint import pprint
      quiet = False
      args = {}
      if len(sys.argv) > 1:
          if sys.argv[1] == '-q':
              quiet = True
              del sys.argv[1]
          args['n'] = int(sys.argv[1])
      input, output = test_explosion(**args)
      if quiet:
          print(len(output))
      else:
          print("Input:")
          pprint(input)
          print()
          print("Output:")
          pprint(output)
  
new_contents: from __future__ import print_function, division, absolute_import
  from fontTools.misc.py23 import *
  from fontTools.varLib.featureVars import (
      overlayFeatureVariations)
  
  
  def test_explosion(n = 10):
      conds = []
      for i in range(n):
          end = i / n
          start = end - 1.
          region = [{'axis': (start, end)}]
          subst = {'g%.2g'%start: 'g%.2g'%end}
          conds.append((region, subst))
      overlaps = overlayFeatureVariations(conds)
      assert len(overlaps) == 2 * n - 1, overlaps
      return conds, overlaps
  
  if __name__ == "__main__":
      import sys
      from pprint import pprint
      quiet = False
      args = {}
      if len(sys.argv) > 1:
          if sys.argv[1] == '-q':
              quiet = True
              del sys.argv[1]
          args['n'] = int(sys.argv[1])
      input, output = test_explosion(**args)
      if quiet:
          print(len(output))
      else:
          print("Input:")
          pprint(input)
          print()
          print("Output:")
          pprint(output)
  
subject: Enable test now that it passes