CI: tweak docstring test to avoid repr issues on some system

conftest.py

@@ -1,5 +1,6 @@
 import os
 import sys
+import builtins
 from subprocess import check_call
 
 import pytest
@@ -453,3 +454,18 @@ def check_array(array, exp_halo, exp_shape, rotate=False):
 
     assert tuple(array.halo) == exp_halo
     assert tuple(shape) == tuple(exp_shape)
+
+
+# Custom display hook that uses __str__ to avoid docstring test issues
+def custom_display_hook(value):
+    if value is not None:
+        builtins._ = value
+        print(str(value))
+
+
+@pytest.fixture(scope='session', autouse=True)
+def use_str_display_hook():
+    original_display_hook = sys.displayhook
+    sys.displayhook = custom_display_hook
+    yield
+    sys.displayhook = original_display_hook  # Restore original display hook after tests