Added teststo utils.py and fixed bugs (#450)

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### Pull Request Checklist:
- [x] This PR addresses an already opened issue (for bug fixes /
features)
    - This PR fixes #xyz
- [x] (If applicable) Documentation has been added / updated (for bug
fixes / features).
- [x] (If applicable) Tests have been added.
- [x] This PR does not seem to break the templates.
- [ ] CHANGELOG.rst has been updated (with summary of main changes).
- [ ] Link to issue (:issue:`number`) and pull request (:pull:`number`)
has been added.

### What kind of change does this PR introduce?

* Adds tests for all functions located in `utils.py`. With the exception
of a few lines impossible to test, everything should be covered.
* The `mask` argument in `stack_drop_nans` can now be a list of
dimensions. In that case, a `dropna(how='all')` operation will be used
to create the mask on-the-fly.
* `convert_calendar` in `xs.utils.clean_up` now uses `xarray` instead of
`xclim`.
* `attrs_to_remove` and `remove_all_attrs_except` in `xs.utils.clean_up`
now use real regex.
* Smaller changes:
  * `minimum_calendar` now accepts a list as input.
  * More calendars are recognized in `translate_time_chunk`
* Multiple entries can now be given for `change_attr_prefix` in
`xs.utils.clean_up`.
* `new_dim` in `unstack_dates` is now None by default and changes
depending on the frequency. It becomes `month` if the data is exactly
monthly, and keep the old default of `season` otherwise.
* Updated the list of libraries in `show_versions` to reflect our
current environment.

* Bug fixes:
  * `maybe_unstack` now works if the dimension name is not the default.
  * `xs.utils.clean_up` now does not also modify the original dataset.
* `unstack_dates` now works correctly for yearly datasets when
`winter_starts_year=True`.
  * `unstack_dates` now works correctly for multi-year frequencies.


### Does this PR introduce a breaking change?

* `convert_calendar` in `xs.utils.clean_up` now uses `xarray` instead of
`xclim`. Keywords aren't compatible between the two, but given that
`xclim` will abandon its function, no backwards compatibility was
sought.
* `attrs_to_remove` and `remove_all_attrs_except` in `xs.utils.clean_up`
now use real regex. It should not be too breaking since a `fullmatch()`
is used, but `*` is now `.*`.

### Other information:

There are 2 lines in `unstack_fill_nan` that I simply don't
understand... They will be covered next week when I can talk to the
author.

CHANGELOG.rst

@@ -6,13 +6,29 @@ v0.9.2 (unreleased)
 -------------------
 Contributors to this version: Juliette Lavoie (:user:`juliettelavoie`), Pascal Bourgault (:user:`aulemahal`), Gabriel Rondeau-Genesse (:user:`RondeauG`).
 
+New features and enhancements
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+* The `mask` argument in ``stack_drop_nans`` can now be a list of dimensions. In that case, a `dropna(how='all')` operation will be used to create the mask on-the-fly. (:pull:`450`).
+* Few changes to ``clean_up``:
+    * The `convert_calendar` function now uses `xarray` instead of `xclim`. (:pull:`450`).
+    * The `attrs_to_remove` and `remove_all_attrs_except` arguments now use real regex. (:pull:`450`).
+    * Multiple entries can now be given for `change_attr_prefix`. (:pull:`450`).
+* ``minimum_calendar`` now accepts a list as input. (:pull:`450`).
+* More calendars are now recognized in ``translate_time_chunk``. (:pull:`450`).
+* `new_dim` in ``unstack_dates`` is now None by default and changes depending on the frequency. It becomes `month` if the data is exactly monthly, and keep the old default of `season` otherwise. (:pull:`450`).
+* Updated the list of libraries in `show_versions` to reflect our current environment. (:pull:`450`).
+
 Bug fixes
 ^^^^^^^^^
 * Fixed bug with reusing weights. (:issue:`411`, :pull:`414`).
 * Fixed bug in `update_from_ds` when "time" is a coordinate, but not a dimension. (:pull: `417`).
 * Avoid modification of mutable arguments in ``search_data_catalogs`` (:pull:`413`).
 * ``ensure_correct_time`` now correctly handles cases where timesteps are missing. (:pull:`440`).
 * If using the argument `tile_buffer` with a `shape` method in ``spatial.subset``, the shapefile will now be reprojected to a WGS84 grid before the buffer is applied. (:pull:`440`).
+* ``maybe_unstack`` now works if the dimension name is not the default. (:pull:`450`).
+* ``unstack_fill_nan`` now works if given a dictionary that contains both dimensions and coordinates. (:pull:`450`).
+* ``clean_up`` no longer modifies the original dataset. (:pull:`450`).
+* ``unstack_dates`` now works correctly for yearly datasets when `winter_starts_year=True`, as well as multi-year datasets. (:pull:`450`).
 
 Internal changes
 ^^^^^^^^^^^^^^^^
@@ -21,6 +37,12 @@ Internal changes
 * Add ``.zip`` and ``.zarr.zip`` as possible file extensions for Zarr datasets. (:pull:`426`).
 * Explicitly assign coords of multiindex in `xs.unstack_fill_nan`. (:pull:`427`).
 * French translations are compiled offline. A new check ensures no PR are merged with missing messages. (:issue:`342`, :pull:`443`).
+* Continued work to add tests. (:pull:`450`).
+
+Breaking changes
+^^^^^^^^^^^^^^^^
+* `convert_calendar` in ``clean_up`` now uses `xarray` instead of `xclim`. Keywords aren't compatible between the two, but given that `xclim` will abandon its function, no backwards compatibility was sought. (:pull:`450`).
+* `attrs_to_remove` and `remove_all_attrs_except` in ``clean_up`` now use real regex. It should not be too breaking since a `fullmatch()` is used, but `*` is now `.*`. (:pull:`450`).
 
 v0.9.1 (2024-06-04)
 -------------------

docs/notebooks/2_getting_started.ipynb

@@ -1389,7 +1389,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "convert_calendar_kwargs = {\"target\": \"standard\"}\n",
+    "convert_calendar_kwargs = {\"calendar\": \"standard\"}\n",
     "missing_by_var = {\"tas\": \"interpolate\"}"
    ]
   },
@@ -1404,14 +1404,11 @@
     "\n",
     "It is possible to write a list of attributes to remove with `attrs_to_remove`, or a list of attributes to keep and remove everything else with `remove_all_attrs_except`. Both take the shape of a dictionnary where the keys are the variables (and 'global' for global attrs) and the values are the list.\n",
     "\n",
-    "The element of the list can be exact matches for the attribute names or use the same regex matching rules as `intake_esm`:\n",
-    "\n",
-    "- ending with a '*' means checks if the substring is contained in the string\n",
-    "- starting with a '^' means check if the string starts with the substring.\n",
+    "The element of the list can be exact matches for the attribute names or use regex matching rules (using a `fullmatch`):\n",
     "\n",
     "Attributes can also be added to datasets using `add_attrs`. This is a dictionary where the keys are the variables and the values are a another dictionary of attributes.\n",
     "\n",
-    "It is also possible to modify the catalogue prefix 'cat:' by a new string with `change_attr_prefix`. Don't use this if this is not the last step of your workflow.\n"
+    "It is also possible to modify the catalogue prefix 'cat:' by a new string with `change_attr_prefix`. Don't use this if this is not the last step of your workflow, as it may break some functions that rely on those prefixes to find the right dataset attributes.\n"
    ]
   },
   {
@@ -1422,15 +1419,15 @@
    "outputs": [],
    "source": [
     "attrs_to_remove = {\n",
-    "    \"tas\": [\"name*\"]\n",
+    "    \"tas\": [\".*name.*\"]\n",
     "}  # remove tas attrs that contain the substring 'name'\n",
     "remove_all_attrs_except = {\n",
-    "    \"global\": [\"^cat:\"]\n",
+    "    \"global\": [\"cat:.*\"]\n",
     "}  # remove all the global attrs EXCEPT for the one starting with cat:\n",
     "add_attrs = {\n",
     "    \"tas\": {\"notes\": \"some crucial information\"}\n",
     "}  # add a new tas attribute named 'notes' with value 'some crucial information'\n",
-    "change_attr_prefix = \"dataset:\"  # change /cat to dataset:"
+    "change_attr_prefix = \"dataset:\"  # change 'cat': to 'dataset:'"
    ]
   },
   {
@@ -1500,7 +1497,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.12.2"
+   "version": "3.12.5"
   }
  },
  "nbformat": 4,