Integration of test into CI/CD worflow

.gitlab-ci.yml

 image: julia:latest
 
 stages:
+  - test         # New stage for running tests
   - documentation
   - deploy
 
+# Test stage for running unit tests with Docker
+test:
+  stage: test
+  services:
+    - docker:dind  # Docker-in-Docker service to allow Docker commands in your job
+  variables:
+    JULIA_PROJECT: "."  # Ensure that Julia uses the project environment
+  before_script:
+    - julia -e 'using Pkg; Pkg.instantiate()'  # Install required packages
+  script:
+    - julia --project=. -e 'using Test; include("test/runtest.jl")'  # Run the tests
+  only:
+    - main
+  tags:
+    - docker  # Optional: tag for specific runners that support Docker
+
+# Documentation stage
 build documentation:
   stage: documentation
   script:
@@ -16,6 +34,7 @@ build documentation:
   only:
     - main
 
+# Deploy stage for GitLab Pages
 pages:
   stage: deploy
   script:
@@ -24,4 +43,4 @@ pages:
     paths:
       - public
   only:
-    - main  
+    - main