diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 67268504a206e42b210bba655e4cec4f1afdc2e0..de776d3eb84c2ab6deb96b32dd0ce300fcb85a5d 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -22,18 +22,19 @@
 variables:
   # this is the image where cpplib repo is present (artifact from pipeline in
   # caosdb-cpplib)
-  CI_REGISTRY_IMAGE_CPPLIB: $CI_REGISTRY/caosdb/src/caosdb-cpplib/testenv:$CPP
+  CPPLIB_TESTENV_IMAGE_TAG: $CI_REGISTRY/caosdb/src/caosdb-cpplib/testenv:$CI_COMMIT_REF_NAME
+  CI_REGISTRY_IMAGE_CPPLIB: $CPPLIB_TESTENV_IMAGE_TAG
   # this is the image where all the docker containers (server, mysql and test
   # suite) are started
   CI_REGISTRY_IMAGE_BASE: $CI_REGISTRY/caosdb/src/caosdb-pyinttest/base:latest
 
   CPPINTTEST_TESTENV_IMAGE_SUFFIX: $CI_COMMIT_REF_NAME
   CPPINTTEST_REPO_PATH: caosdb/src/caosdb-cppinttest
-  CPPINTTEST_TESTENV_IMAGE_TAG: ${CPPINTTEST_REPO_PATH}/testenv:${CPPINTTEST_IMAGE_SUFFIX}
+  CPPINTTEST_TESTENV_IMAGE_TAG: $CPPINTTEST_REPO_PATH/testenv:$CPPINTTEST_IMAGE_SUFFIX
   # this is the image where the cpplib is installed and where the testsuite runs
-  CPPINTTEST_REGISTRY_IMAGE: ${CI_REGISTRY}/${CPPINTTEST_TESTENV_IMAGE_TAG}
+  CPPINTTEST_REGISTRY_IMAGE: $CI_REGISTRY/$CPPINTTEST_TESTENV_IMAGE_TAG
   # this is the name of the image in the /image-cache/ directory
-  CPPINTTEST_IMAGE_CACHE: ${CPPINTTEST_TESTENV_IMAGE_TAG}.tar
+  CPPINTTEST_IMAGE_CACHE: $CPPINTTEST_TESTENV_IMAGE_TAG.tar
 
 
   ## FOR DEBUGGING