ci: added BEC_CORE_BRANCH var name to .gitlab-ci.yml

.gitlab-ci.yml

@@ -3,6 +3,9 @@
 # https://hub.docker.com/r/library/python/tags/
 image: $CI_DOCKER_REGISTRY/python:3.10
 
+variables:
+  BEC_CORE_BRANCH: "master"
+
 workflow:
   rules:
     - if: $CI_PIPELINE_SOURCE == "merge_request_event"
@@ -85,6 +88,8 @@ secret_detection:
 pytest:
   stage: test
   script:
+    - git clone --branch $BEC_CORE_BRANCH https://gitlab.psi.ch/bec/bec.git
+    - pip install -e ./bec/bec_lib[dev]
     - pip install coverage
     - coverage run --source=./ophyd_devices -m pytest -v --junitxml=report.xml --random-order --full-trace ./tests
     - coverage report