Add genesis sync test to CI (#7561)

* #7550

Use existing code from  @jimmygchen in #7530 and modify for genesis sync test. Thanks @jimmygchen !

.github/workflows/local-testnet.yml

@@ -20,7 +20,7 @@ jobs:
 
       - name: Build Docker image
         run: |
-          docker build --build-arg FEATURES=portable -t lighthouse:local .
+          docker build --build-arg FEATURES=portable,spec-minimal -t lighthouse:local .
           docker save lighthouse:local -o lighthouse-docker.tar
 
       - name: Upload Docker image artifact
@@ -213,6 +213,49 @@ jobs:
             scripts/local_testnet/logs
           retention-days: 3
 
+  # Test syncing from genesis on a local testnet. Aims to cover forward syncing both short and long distances.
+  genesis-sync-test:
+    name: genesis-sync-test-${{ matrix.fork }}-${{ matrix.offline_secs }}s
+    runs-on: ubuntu-latest
+    needs: dockerfile-ubuntu
+    if: contains(github.event.pull_request.labels.*.name, 'syncing')
+    strategy:
+      matrix:
+        fork: [electra, fulu]
+        offline_secs: [120, 300]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Kurtosis
+        run: |
+          echo "deb [trusted=yes] https://apt.fury.io/kurtosis-tech/ /" | sudo tee /etc/apt/sources.list.d/kurtosis.list
+          sudo apt update
+          sudo apt install -y kurtosis-cli
+          kurtosis analytics disable
+
+      - name: Download Docker image artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: lighthouse-docker
+          path: .
+
+      - name: Load Docker image
+        run: docker load -i lighthouse-docker.tar
+
+      - name: Run the genesis sync test script
+        run: |
+          ./genesis-sync.sh "sync-${{ matrix.fork }}-${{ matrix.offline_secs }}s" "genesis-sync-config-${{ matrix.fork }}.yaml" "${{ matrix.fork }}" "${{ matrix.offline_secs }}"
+        working-directory: scripts/tests
+
+      - name: Upload logs artifact
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: logs-genesis-sync-${{ matrix.fork }}-${{ matrix.offline_secs }}s
+          path: |
+            scripts/local_testnet/logs
+          retention-days: 3
+
   # This job succeeds ONLY IF all others succeed. It is used by the merge queue to determine whether
   # a PR is safe to merge. New jobs should be added here.
   local-testnet-success:
@@ -228,5 +271,5 @@ jobs:
       - uses: actions/checkout@v4
       - name: Check that success job is dependent on all others
         run: |
-          exclude_jobs='checkpoint-sync-test'
+          exclude_jobs='checkpoint-sync-test|genesis-sync-test'
           ./scripts/ci/check-success-job.sh ./.github/workflows/local-testnet.yml local-testnet-success "$exclude_jobs"