What are GitHub Actions artifacts? How do you upload and download them?

jobs:
  test:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v4

      - name: Run tests
        run: mvn test
        continue-on-error: true    # don't stop if tests fail

      - name: Upload Surefire reports
        if: always()               # upload even if tests failed
        uses: actions/upload-artifact@v4
        with:
          name: surefire-reports
          path: target/surefire-reports/
          retention-days: 14       # keep for 14 days (default 90)

      - name: Upload Allure results
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: allure-results
          path: target/allure-results/

      - name: Upload screenshots on failure
        if: failure()
        uses: actions/upload-artifact@v4
        with:
          name: failure-screenshots-${{ github.run_number }}
          path: screenshots/

      - name: Upload built JAR
        uses: actions/upload-artifact@v4
        with:
          name: app-jar
          path: target/*.jar

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: mvn clean package -DskipTests
      - uses: actions/upload-artifact@v4
        with:
          name: app-jar
          path: target/*.jar

  deploy:
    needs: build
    runs-on: ubuntu-latest
    steps:
      - name: Download built JAR
        uses: actions/download-artifact@v4
        with:
          name: app-jar
          path: ./artifacts/

      - name: Deploy
        run: |
          ls -la ./artifacts/
          ./deploy.sh ./artifacts/myapp-1.0.jar

- uses: actions/upload-artifact@v4
  with:
    name: test-results
    path: |
      target/surefire-reports/
      target/extent-reports/
      screenshots/
      logs/*.log

- name: Download all artifacts
  uses: actions/download-artifact@v4
  # No 'name' = downloads all artifacts into separate directories
  with:
    path: all-artifacts/

- run: ls -la all-artifacts/
# all-artifacts/
# ├── surefire-reports/
# ├── allure-results/
# └── app-jar/

strategy:
  matrix:
    browser: [chrome, firefox]

steps:
  - name: Upload results
    if: always()
    uses: actions/upload-artifact@v4
    with:
      name: test-results-${{ matrix.browser }}   # unique name per matrix job
      path: target/surefire-reports/