skip testing test_checked_session.py if pydantic is not installed

Author: alixdamman

larray/tests/test_checked_session.py

@@ -1,6 +1,11 @@
 import pytest
-import pickle
 
+try:
+    import pydantic
+except ImportError:
+    pytestmark = pytest.skip("pydantic is required for testing Checked* classes")
+
+import pickle
 import numpy as np
 
 from larray import (CheckedSession, CheckedArray, Axis, AxisCollection, Group, Array,