test: add test_gpy_not_supported_on_py311_exception

tests/test_samplers/test_gaussian_process.py

@@ -14,12 +14,14 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 """This module contains tests for the Gaussian process sampler."""
+import unittest.mock
 from typing import Optional, Tuple, cast
 
 import numpy as np
 import pytest
 from numpy.typing import NDArray
 
+from black_it._load_dependency import GPyNotSupportedOnPy311Exception
 from black_it.samplers.gaussian_process import GaussianProcessSampler, _AcquisitionTypes
 from black_it.search_space import SearchSpace
 from tests.utils.base import no_gpy_installed, no_python311_for_gpy
@@ -151,3 +153,18 @@ def test_dependency_not_installed_error() -> None:
             r"To solve the issue, you can install the extra 'gp-sampler': pip install black-it\[gp-sampler\]"
         ),
     )
+
+
+def test_gpy_not_supported_on_py311_exception() -> None:
+    """Test the "GPyNotSupportedOnPy311Exception" exception in case the GPy package is not supported on Python 3.11."""
+    with unittest.mock.patch("sys.version_info", new=(3, 11, 0, "final", 0)):
+        generic_test_import_error(
+            module_dotted_path="black_it.samplers.gaussian_process",
+            import_error_global_variable_name="_GPY_IMPORT_ERROR",
+            component_initializer=lambda: GaussianProcessSampler(4),
+            expected_message_pattern=(
+                "The GaussianProcessSampler depends on 'GPy', which is not supported on Python 3.11; "
+                "see https://github.com/bancaditalia/black-it/issues/36"
+            ),
+            expected_exception_cls=GPyNotSupportedOnPy311Exception,
+        )