diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 67fae9b160b0a9816ea83bff1be619125ded68d0..70c5ea943bb4bfc4087a4d0f4281fcc756e63a6f 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -18,6 +18,7 @@ build-openapi-scheme:
   variables:
     OPENAPI_JSON: ./public/api.json
   before_script:
+    # we do this, because YAML anchors are not supported when executing locally
     - apt-get update
     - apt-get install -y gcc libldap2-dev libsasl2-dev libmagic-dev
     - pip install --upgrade pip
@@ -33,13 +34,14 @@ build-openapi-scheme:
 
 run_test_cases:
   stage: test
-  image: python:3.11
+  image: python:3.11-slim
   before_script:
-  - apt-get -qq update
-  - apt-get -y install curl pip libsasl2-dev libldap2-dev libssl-dev
-  - python3 -m pip install --upgrade pip
-  - pip install poetry
-  - poetry install --no-interaction
+    # we do this, because YAML anchors are not supported when executing locally
+    - apt-get -qq update
+    - apt-get install -y gcc libldap2-dev libsasl2-dev libmagic-dev
+    - python3 -m pip install --upgrade pip
+    - python3 -m pip install poetry
+    - poetry install --no-interaction
   script:
     - mkdir logs
     - make coverage