Fix for xarray v2023.12.0 (#294)

* fix import of xarray.testing internals that was changed by pydata/xarray#8404

* bump minimum required version of xarray

* linting

datatree/testing.py

@@ -1,4 +1,4 @@
-from xarray.testing import ensure_warnings
+from xarray.testing.assertions import ensure_warnings
 
 from .datatree import DataTree
 from .formatting import diff_tree_repr

docs/source/whats-new.rst

@@ -26,6 +26,10 @@ New Features
 Breaking changes
 ~~~~~~~~~~~~~~~~
 
+- Minimum required version of xarray is now 2023.12.0, i.e. the latest version.
+  This is required to prevent recent changes to xarray's internals from breaking datatree.
+  (:issue:`293`, :pull:`294`)
+  By `Tom Nicholas <https://github.com/TomNicholas>`_.
 - Change default write mode of :py:meth:`DataTree.to_zarr` to ``'w-'`` to match ``xarray``
   default and prevent accidental directory overwrites. (:issue:`274`, :pull:`275`)
   By `Sam Levang <https://github.com/slevang>`_.

pyproject.toml

@@ -19,7 +19,7 @@ classifiers = [
 ]
 requires-python = ">=3.9"
 dependencies = [
-    "xarray >=2022.6.0",
+    "xarray >=2023.12.0",
     "packaging",
 ]
 dynamic = ["version"]