Silence dask doctest warning (#8734)

* Silence dask doctest warning

Closes #8732. Not the most elegant implementation but it's only temporary

Author: max-sixty

ci/requirements/environment.yml

@@ -9,6 +9,7 @@ dependencies:
   - cartopy
   - cftime
   - dask-core
+  - dask-expr # dask raises a deprecation warning without this, breaking doctests
   - distributed
   - flox
   - fsspec!=2021.7.0
@@ -32,7 +33,7 @@ dependencies:
   - pip
   - pooch
   - pre-commit
-  - pyarrow # pandas makes a deprecation warning without this, breaking doctests
+  - pyarrow # pandas raises a deprecation warning without this, breaking doctests
   - pydap
   - pytest
   - pytest-cov

conftest.py

@@ -39,3 +39,11 @@ def add_standard_imports(doctest_namespace, tmpdir):
 
     # always switch to the temporary directory, so files get written there
     tmpdir.chdir()
+
+    # Avoid the dask deprecation warning, can remove if CI passes without this.
+    try:
+        import dask
+    except ImportError:
+        pass
+    else:
+        dask.config.set({"dataframe.query-planning": True})