Add testing job to GitHub Actions workflow for Docker image build

.github/workflows/docker.yml

@@ -6,8 +6,27 @@ on:
       - '**' # Esto aplica para cualquier rama
 
 jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout del código
+        uses: actions/checkout@v4
+      - name: Configurar Python
+        uses: actions/setup-python@v6
+        with:
+          python-version: '3.14'
+      - name: Instalar dependencias
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt
+      - name: Ejecutar tests
+        env:
+          DJANGO_SETTINGS_MODULE: proyecto.settings
+        run: |
+          python manage.py test
   docker:
     runs-on: ubuntu-latest
+    needs: test
     permissions:
       contents: read
       packages: write # Necesario para subir a GHCR