Edit .gitlab-ci.yml

explicitly install pytest 

.gitlab-ci.yml

@@ -15,6 +15,7 @@ variables:
     - git checkout "$CI_COMMIT_REF_NAME"
   script:
     - pip install .[testing]
+    - pip install pytest pytest-cov  # Explicitly install testing deps
     - pytest --cov --cov-report term-missing --cov-report xml:coverage.xml --cov-report html:cov_html
     - ls -la ./
   coverage: '/(?i)total.*? (100(?:\.0+)?\%|[1-9]?\d(?:\.\d+)?\%)$/'