feat: automatic testing

This commit adds a .gitlab-ci.yml file, which is responsible for
defining jobs to be run (in this case only running the test suite)

ref: N25B-65

.gitlab-ci.yml

@@ -0,0 +1,26 @@
+# ---------- GLOBAL SETUP ---------- #
+workflow:
+  rules:
+    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
+
+stages:
+  - install
+  - lint
+  - test
+
+variables:
+  UV_VERSION: "0.9.4"
+  PYTHON_VERSION: "3.13"
+  BASE_LAYER: trixie-slim
+
+default:
+  image: ghcr.io/astral-sh/uv:$UV_VERSION-python$PYTHON_VERSION-$BASE_LAYER
+
+# ---------- TESTING ---------- #
+test:
+  stage: test
+  tags:
+    - test
+  script:
+    - uv run --only-group test pytest
+