def test_prefilter():
 pairs = [('2+2', '2+2')]
 for (raw, correct) in pairs:
  nt.assert_equal(ip.prefilter(raw), correct)

def test_prefilter ( ) : pairs = [ ( '2+2' , '2+2' ) ] for ( raw , correct ) in pairs : nt . assert_equal ( ip . prefilter ( raw ) , correct )
test user input conversions .