replace artefact download by caching in backend unit test job

.github/workflows/test-backend.yml

@@ -10,6 +10,7 @@ jobs:
     outputs:
       backend: ${{ steps.changes.outputs.backend }}
       docker: ${{ steps.changes.outputs.docker }}
+      pr-number: ${{ steps.pr.outputs.number }}
     steps:
       - uses: actions/checkout@v3.3.0
 
@@ -21,6 +22,10 @@ jobs:
           filters: .github/file-filters.yml
           list-files: shell
 
+      - name: Get pr number
+        id: pr
+        uses: 8BitJonny/gh-get-current-pr@2.2.0
+
   build_test_neo4j:
     name: Docker Build Test - Neo4J
     if: needs.files-changed.outputs.backend == 'true' || needs.files-changed.outputs.docker == 'true'
@@ -34,17 +39,13 @@ jobs:
         run: |
           docker build --target community -t "ocelotsocialnetwork/neo4j-community:test" neo4j/
           docker save "ocelotsocialnetwork/neo4j-community:test" > /tmp/neo4j.tar
-
-      - name: Get pr number
-        id: pr
-        uses: 8BitJonny/gh-get-current-pr@2.2.0
       
       - name: Cache docker images
         id: cache-neo4j
         uses: actions/cache/save@v3.3.1
         with:
           path: /tmp/neo4j.tar
-          key: backend-neo4j-cache-pr${{ steps.pr.outputs.number }}
+          key: backend-neo4j-cache-pr${{ needs.files-changed.outputs.pr-number }}
 
   build_test_backend:
     name: Docker Build Test - Backend
@@ -59,17 +60,13 @@ jobs:
         run: |
           docker build --target test -t "ocelotsocialnetwork/backend:test" backend/
           docker save "ocelotsocialnetwork/backend:test" > /tmp/backend.tar
-
-      - name: Get pr number
-        id: pr
-        uses: 8BitJonny/gh-get-current-pr@2.2.0
       
       - name: Cache docker images
         id: cache-backend
         uses: actions/cache/save@v3.3.1
         with:
           path: /tmp/backend.tar
-          key: backend-cache-pr${{ steps.pr.outputs.number }}
+          key: backend-cache-pr${{ needs.files-changed.outputs.pr-number }}
 
   lint_backend:
     name: Lint Backend
@@ -94,23 +91,24 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v3
 
-      - name: Download Docker Image (Neo4J)
-        uses: actions/download-artifact@v3
+      - name: Restore Neo4J cache
+        uses: actions/cache/restore@v3.3.1
         with:
-          name: docker-neo4j-image
-          path: /tmp
+          path: /tmp/neo4j.tar
+          key: backend-neo4j-cache-pr${{ needs.files-changed.outputs.pr-number }}
+          fail-on-cache-miss: true
 
-      - name: Load Docker Image
-        run: docker load < /tmp/neo4j.tar
+      - name: Restore Backend cache
+        uses: actions/cache/restore@v3.3.1
+        with:
+          path: /tmp/backend.tar
+          key: backend-cache-pr${{ needs.files-changed.outputs.pr-number }}
+          fail-on-cache-miss: true
 
-      # - name: Download Docker Image (Backend)
-      #   uses: actions/download-artifact@v3
-      #   with:
-      #     name: docker-backend-test
-      #     path: /tmp
-
-      - name: Load Docker Image
-        run: docker load < /tmp/backend.tar
+      - name: Load Docker Images
+        run: |
+          docker load < /tmp/neo4j.tar
+          docker load < /tmp/backend.tar
 
       - name: backend | copy env files webapp
         run: cp webapp/.env.template webapp/.env