TST: skip some timedelta plotting tests on mac (on travis) for precision display issues

xref #15067

Author: jreback

doc/source/whatsnew/v0.20.0.txt

@@ -156,6 +156,7 @@ Other enhancements
 - ``DataFrame.to_excel()`` has a new ``freeze_panes`` parameter to turn on Freeze Panes when exporting to Excel (:issue:`15160`)
 - HTML table output skips ``colspan`` or ``rowspan`` attribute if equal to 1. (:issue:`15403`)
 - ``pd.TimedeltaIndex`` now has a custom datetick formatter specifically designed for nanosecond level precision (:issue:`8711`)
+
 .. _ISO 8601 duration: https://en.wikipedia.org/wiki/ISO_8601#Durations
 
 .. _whatsnew_0200.api_breaking:

pandas/tests/plotting/test_datetimelike.py

@@ -7,7 +7,7 @@
 
 import numpy as np
 from pandas import Index, Series, DataFrame
-
+from pandas.compat import is_platform_mac
 from pandas.tseries.index import date_range, bdate_range
 from pandas.tseries.tdi import timedelta_range
 from pandas.tseries.offsets import DateOffset
@@ -1272,6 +1272,8 @@ def test_plot_outofbounds_datetime(self):
         self.plt.plot(values)
 
     def test_format_timedelta_ticks_narrow(self):
+        if is_platform_mac():
+            pytest.skip("skip on mac for precision display issue on older mpl")
 
         expected_labels = [
             '00:00:00.00000000{:d}'.format(i)
@@ -1288,6 +1290,8 @@ def test_format_timedelta_ticks_narrow(self):
             self.assertEqual(l.get_text(), l_expected)
 
     def test_format_timedelta_ticks_wide(self):
+        if is_platform_mac():
+            pytest.skip("skip on mac for precision display issue on older mpl")
 
         expected_labels = [
             '00:00:00',