issue_comments

Great! Quite an effort @keewis —thank you!

I think these tests are unrelated and we can merge?

```python

=================================== FAILURES =================================== ____ testdatetime_reduce[False] ______

dask = False

@arm_xfail
@pytest.mark.parametrize("dask", [False, True])
def test_datetime_reduce(dask):
    time = np.array(pd.date_range("15/12/1999", periods=11))
    time[8:11] = np.nan
    da = DataArray(np.linspace(0, 365, num=11), dims="time", coords={"time": time})

    if dask and has_dask:
        chunks = {"time": 5}
        da = da.chunk(chunks)

    actual = da["time"].mean()

  assert not pd.isnull(actual)

E AssertionError: assert not True E + where True = <function isna at 0x7fcbdefdbae8>(<xarray.DataArray 'time' ()>\narray('NaT', dtype='datetime64[ns]')) E + where <function isna at 0x7fcbdefdbae8> = pd.isnull

xarray/tests/test_duck_array_ops.py:288: AssertionError ____ test_datetime_reduce[True] ______

dask = True

@arm_xfail
@pytest.mark.parametrize("dask", [False, True])
def test_datetime_reduce(dask):
    time = np.array(pd.date_range("15/12/1999", periods=11))
    time[8:11] = np.nan
    da = DataArray(np.linspace(0, 365, num=11), dims="time", coords={"time": time})

    if dask and has_dask:
        chunks = {"time": 5}
        da = da.chunk(chunks)

    actual = da["time"].mean()

  assert not pd.isnull(actual)

E AssertionError: assert not True E + where True = <function isna at 0x7fcbdefdbae8>(<xarray.DataArray 'time' ()>\narray('NaT', dtype='datetime64[ns]')) E + where <function isna at 0x7fcbdefdbae8> = pd.isnull ```

Added integration tests against pint <https://pint.readthedocs.io/>_. Note that these tests currently require a special version of pint to run and are otherwise skipped. Also note that at the moment of writing, there are issues when pint interacts with non-numpy array libraries, e.g. dask or sparse.

(remove emphasis in actual version)

readers will be much more interested in what they can actually do with pint

👍 , let's add a sentence

OK great! @crusaderky any final thoughts? Anyone else?

I assumed this to be the same as datetime, which means object labels instead of strings. So now only the top-level functions and dataset are missing.

👍

In general we've tried to make identical as exactly identical, including types etc, so I think different units would return False there

Great! This is going to be exciting. Ping here for any questions!

From what is already done, mypy . fails because of pint (this the same as with quantities in #2956). What would I do to fix that?

V easy - add to setup.cfg like other libraries listed there