@@ -1594,19 +1594,47 @@ def test_engformatter_usetex_useMathText():
15941594assert x_tick_label_text == ['$0$' ,'$500$' ,'$1$ k' ]
15951595
15961596
1597- def test_engformatter_useOffset ():
1597+ @pytest .mark .parametrize (
1598+ 'oom_center, oom_noise' , [
1599+ (15 ,6 ),
1600+ (12 ,3 ),
1601+ (9 ,3 ),
1602+ (9 ,6 ),
1603+ (0 ,- 6 ),
1604+ # Going to lower orders of magnitudes will make this test fail due to
1605+ # floating points approximated as zero. Putting 12 and above oom difference
1606+ # between center and the noise will also fail, due to ticks give different
1607+ # unit prefixes
1608+ ]
1609+ )
1610+ def test_engformatter_offset (oom_center ,oom_noise ):
1611+ UNIT = "eV"
1612+ # Intentionally picking also negative numbers
1613+ r = range (- 2 ,9 )
15981614fig ,ax = plt .subplots ()
1599- data_offset = 10000000
1600- ydata = range ( data_offset , data_offset + 5 )
1615+ data_offset = 10 ** oom_center
1616+ ydata = data_offset + np . array ( r , dtype = float ) * 10 ** oom_noise
16011617ax .plot (ydata )
16021618ax .set_yticks (ydata )
1603- ax .yaxis .set_major_formatter (mticker .EngFormatter (useOffset = True ,unit = "Hz" ))
1619+ formatter = mticker .EngFormatter (useOffset = True ,unit = UNIT )
1620+ ax .yaxis .set_major_formatter (formatter )
16041621fig .canvas .draw ()
1605- y_tick_label_text = [labl .get_text ()for labl in ax .get_yticklabels ()]
1606- offset = ax .yaxis .get_major_formatter ().get_offset ()
1607- expectedTicks = list (map ("{} Hz" .format ,np .array (ydata )- data_offset ))
1608- assert y_tick_label_text == expectedTicks
1609- assert "+10 MHz" == offset
1622+ ticksGot = [labl .get_text ()for labl in ax .get_yticklabels ()]
1623+ ticksExpected = list (map (
1624+ # Fix negative number's - sign in case unicode is used
1625+ lambda n :formatter .fix_minus (str (n ))+ " " + (
1626+ # zero is zero, no matter what is the oom
1627+ formatter .ENG_PREFIXES [oom_noise ]if n != 0 else ""
1628+ )+ UNIT ,
1629+ r
1630+ ))
1631+ offsetGot = ax .yaxis .get_major_formatter ().get_offset ()
1632+ offsetExpected = "+1 {}{}" .format (
1633+ formatter .ENG_PREFIXES [oom_center ],
1634+ UNIT
1635+ )
1636+ assert ticksGot == ticksExpected
1637+ assert offsetExpected == offsetGot
16101638
16111639
16121640class TestPercentFormatter :