[CI] Fix unit tests

Author: stephane-caron

tests/__init__.py

@@ -14,3 +14,17 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+from .test_clone_to_cache import TestCloneToCache
+from .test_clone_to_directory import TestCloneToDirectory
+from .test_descriptions import TestDescriptions
+from .test_loaders import TestLoaders
+from .test_progress_bar import TestProgressBar
+
+__all__ = [
+    "TestCloneToCache",
+    "TestCloneToDirectory",
+    "TestDescriptions",
+    "TestLoaders",
+    "TestProgressBar",
+]