Try switching it back to Poetry with the env use statement

ci/package-build.template.yml

@@ -9,10 +9,11 @@
         - cd ${PACKAGE_PATH}
 
         # Install build, poetry and pytest
-        - pip install build poetry pytest fakeredis
+        - pip install poetry
+        - poetry env use $(which python3)
 
         # Install the package for testing
-        - pip install .
+        - poetry install --with test .
         - pytest test
 
         # Build the package and push to the gitlab repo