Adjust test to find xclim location via importlib (#2028)

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

* The `TestOfficialYaml` test now uses a dynamic method for locating the
installed location of `xclim`.

### Does this PR introduce a breaking change?

No.

### Other information:

When xclim is installed, there is no guarantee that `src` will be the
top-level folder. This is by design to ensure that we don't write tests
that try to navigate the folder-tree of `xclim` using relative paths
from the `tests` folder. Seeing as this is the only failing test on
`conda-forge`, I think we're doing an OK job.

Commit that bypasses this problem on conda-forge:
conda-forge/xclim-feedstock@f1886ee

CHANGELOG.rst

@@ -19,6 +19,7 @@ New features and enhancements
 Internal changes
 ^^^^^^^^^^^^^^^^
 * `sphinx-codeautolink` and `pygments` have been temporarily pinned due to breaking API changes. (:pull:`2030`).
+* Adjusted the ``TestOfficialYaml`` test to use a dynamic method for finding the installed location of `xclim`. (:pull:`2028`).
 
 v0.54.0 (2024-12-16)
 --------------------

tests/test_modules.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from importlib.util import find_spec
 from inspect import _empty  # noqa
 from pathlib import Path
 
@@ -264,7 +265,7 @@ def test_validate(tmp_path):
 
 
 class TestOfficialYaml(yamale.YamaleTestCase):
-    base_dir = str(Path(__file__).parent.parent / "src" / "xclim" / "data")
+    base_dir = str(Path(find_spec("xclim").origin).parent.joinpath("data"))
     schema = "schema.yml"
     yaml = ["cf.yml", "anuclim.yml", "icclim.yml"]