def test_resample_first(self):
times = pd.date_range('2000-01-01', freq='6H', periods=10)
array = DataArray(np.arange(10), [('time', times)])
actual = array.resample('1D', dim='time', how='first')
expected = DataArray([0, 4, 8], [('time', times[::4])])
self.assertDataArrayIdentical(expected, actual)
# verify that labels don't use the first value
actual = array.resample('24H', dim='time', how='first')
expected = DataArray(array.to_series().resample('24H', how='first'))
self.assertDataArrayIdentical(expected, actual)
# missing values
array = array.astype(float)
array[:2] = np.nan
actual = array.resample('1D', dim='time', how='first')
expected = DataArray([2, 4, 8], [('time', times[::4])])
self.assertDataArrayIdentical(expected, actual)
actual = array.resample('1D', dim='time', how='first', skipna=False)
expected = DataArray([np.nan, 4, 8], [('time', times[::4])])
self.assertDataArrayIdentical(expected, actual)
