Merge remote-tracking branch 'upstream/master' into fix/groupby-nan

* upstream/master:
  Whatsnew for pydata#3419 (pydata#3422)
  Revert changes made in pydata#3358 (pydata#3411)
  Python3.6 idioms (pydata#3419)
  Temporarily mark pseudonetcdf-3.1 as incompatible (pydata#3420)
  Fix and add test for groupby_bins() isnan TypeError. (pydata#3405)
  Update where docstring to make return value type more clear (pydata#3408)
  tests for arrays with units (pydata#3238)

Author: dcherian

ci/requirements/py36-min-all-deps.yml

@@ -31,6 +31,7 @@ dependencies:
   - numba=0.44
   - numpy=1.14
   - pandas=0.24
+  # - pint  # See py36-min-nep18.yml
   - pip
   - pseudonetcdf=3.0
   - pydap=3.2

ci/requirements/py36-min-nep18.yml

@@ -2,14 +2,15 @@ name: xarray-tests
 channels:
   - conda-forge
 dependencies:
-  # Optional dependencies that require NEP18, such as sparse,
+  # Optional dependencies that require NEP18, such as sparse and pint,
   # require drastically newer packages than everything else
   - python=3.6
   - coveralls
   - dask=2.4
   - distributed=2.4
   - numpy=1.17
   - pandas=0.24
+  - pint=0.9  # Actually not enough as it doesn't implement __array_function__yet!
   - pytest
   - pytest-cov
   - pytest-env

ci/requirements/py36.yml

@@ -27,8 +27,9 @@ dependencies:
   - numba
   - numpy
   - pandas
+  - pint
   - pip
-  - pseudonetcdf
+  - pseudonetcdf<3.1  # FIXME https://github.com/pydata/xarray/issues/3409
   - pydap
   - pynio
   - pytest

ci/requirements/py37-windows.yml

@@ -27,8 +27,9 @@ dependencies:
   - numba
   - numpy
   - pandas
+  - pint
   - pip
-  - pseudonetcdf
+  - pseudonetcdf<3.1  # FIXME https://github.com/pydata/xarray/issues/3409
   - pydap
   # - pynio  # Not available on Windows
   - pytest

ci/requirements/py37.yml

@@ -27,8 +27,9 @@ dependencies:
   - numba
   - numpy
   - pandas
+  - pint
   - pip
-  - pseudonetcdf
+  - pseudonetcdf<3.1  # FIXME https://github.com/pydata/xarray/issues/3409
   - pydap
   - pynio
   - pytest

doc/gallery/plot_cartopy_facetgrid.py

@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 ==================================
 Multiple plots and map projections

doc/gallery/plot_colorbar_center.py

@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 ==================
 Centered colormaps

doc/gallery/plot_control_colorbar.py

@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 ===========================
 Control the plot's colorbar

doc/gallery/plot_lines_from_2d.py

@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 ==================================
 Multiple lines from a 2d DataArray

doc/gallery/plot_rasterio.py

@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 .. _recipes.rasterio: