issues: 941808931

What happened:

The test suite failed: ```pytb =================================== FAILURES =================================== ____ TestDataset.test_resample_loffset _____

self = <xarray.tests.test_dataset.TestDataset object at 0xe6ccde68>

def test_resample_loffset(self):
    times = pd.date_range("2000-01-01", freq="6H", periods=10)
    ds = Dataset(
        {
            "foo": (["time", "x", "y"], np.random.randn(10, 5, 3)),
            "bar": ("time", np.random.randn(10), {"meta": "data"}),
            "time": times,
        }
    )
    ds.attrs["dsmeta"] = "dsdata"

    # Our use of `loffset` may change if we align our API with pandas' changes.
    # ref https://github.com/pydata/xarray/pull/4537
    actual = ds.resample(time="24H", loffset="-12H").mean().bar
    expected_ = ds.bar.to_series().resample("24H").mean()
    expected_.index += to_offset("-12H")
    expected = DataArray.from_series(expected_)

  assert_identical(actual, expected)

E AssertionError: Left and right DataArray objects are not identical E
E Differing values: E L E array([ 0.018477, -0.178807, -0.792644]) E R E array([ 0.018477, -0.178807, -0.792644])

actual = <xarray.DataArray 'bar' (time: 3)> array([ 0.01847694, -0.1788066 , -0.79264435]) Coordinates: * time (time) datetime64[ns] 1999-12-31T12:00:00 ... 2000-01-02T12:00:00 ds = <xarray.Dataset> Dimensions: (time: 10, x: 5, y: 3) Coordinates: * time (time) datetime64[ns] 2000-01-01 ... 2000-01-03T06:00:00 Dimensions without coordinates: x, y Data variables: foo (time, x, y) float64 1.764 0.4002 0.9787 ... 1.117 -1.316 -0.4616 bar (time) float64 -0.06824 1.713 -0.7448 ... -1.08 -1.147 -0.4378 Attributes: dsmeta: dsdata expected = <xarray.DataArray 'bar' (time: 3)> array([ 0.01847694, -0.1788066 , -0.79264435]) Coordinates: * time (time) datetime64[ns] 1999-12-31T12:00:00 ... 2000-01-02T12:00:00 expected_ = time 1999-12-31 12:00:00 0.018477 2000-01-01 12:00:00 -0.178807 2000-01-02 12:00:00 -0.792644 Freq: 24H, Name: bar, dtype: float64 self = <xarray.tests.test_dataset.TestDataset object at 0xe6ccde68> times = DatetimeIndex(['2000-01-01 00:00:00', '2000-01-01 06:00:00', '2000-01-01 12:00:00', '2000-01-01 18:00:00', '2000-01-02 00:00:00', '2000-01-02 06:00:00', '2000-01-02 12:00:00', '2000-01-02 18:00:00', '2000-01-03 00:00:00', '2000-01-03 06:00:00'], dtype='datetime64[ns]', freq='6H')

/var/tmp/portage/dev-python/xarray-0.18.2-r1/work/xarray-0.18.2/xarray/tests/test_dataset.py:3991: AssertionError =============================== warnings summary =============================== ```

What you expected to happen: Test suite passing ;-).

Minimal Complete Verifiable Example:

n/a (xarray test suite problem)

Anything else we need to know?:

This happens on 32-bit i686 system but not on amd64. I suppose it's a precision problem.

Environment: