old_contents: # standard modules
  import StringIO
  from unittest import TestCase
  
  # custom modules
  from iago.DatabaseProvider import DB
  
  
  class TestDB(TestCase):
  	def test_read_empty(self):
  		s = StringIO.StringIO('{}')
  		d = DB()
  		try:
  			d.read(s)
  		except KeyError:
  			self.fail('DB cannot handle empty JSON files.')
  
new_contents: # standard modules
  import StringIO
  from unittest import TestCase
  
  # custom modules
  from iago.DatabaseProvider import DB
  
  
  class TestDB(TestCase):
  	def test_read_empty(self):
  		s = StringIO.StringIO('{}')
  		d = DB()
  		try:
  			d.read(s, format='json')
  		except KeyError:
  			self.fail('DB cannot handle empty JSON files.')
  
subject: Fix test to specify file format