def helper_test_split(test_case, test_series: TimeSeries):
seriesA, seriesB = test_series.split_after(pd.Timestamp('20130104'))
test_case.assertEqual(seriesA.end_time(), pd.Timestamp('20130104'))
test_case.assertEqual(seriesB.start_time(), pd.Timestamp('20130105'))
seriesC, seriesD = test_series.split_before(pd.Timestamp('20130104'))
test_case.assertEqual(seriesC.end_time(), pd.Timestamp('20130103'))
test_case.assertEqual(seriesD.start_time(), pd.Timestamp('20130104'))
test_case.assertEqual(test_series.freq_str(), seriesA.freq_str())
test_case.assertEqual(test_series.freq_str(), seriesC.freq_str())
def helper_test_drop(test_case, test_series: TimeSeries):
seriesA = test_series.drop_after(pd.Timestamp('20130105'))
test_case.assertEqual(seriesA.end_time(),
pd.Timestamp('20130105') - test_series.freq())
test_case.assertTrue(
np.all(seriesA.time_index() < pd.Timestamp('20130105')))
seriesB = test_series.drop_before(pd.Timestamp('20130105'))
test_case.assertEqual(seriesB.start_time(),
pd.Timestamp('20130105') + test_series.freq())
test_case.assertTrue(
np.all(seriesB.time_index() > pd.Timestamp('20130105')))
test_case.assertEqual(test_series.freq_str(), seriesA.freq_str())
test_case.assertEqual(test_series.freq_str(), seriesB.freq_str())