fix(ci): start AltTester Desktop headless before Unity 6 macOS UI tests

Author: rodrigo-fournier-immutable

.github/workflows/ui-tests.yml

@@ -147,6 +147,26 @@ jobs:
           python-version: "3.13"
       - name: Install dependencies
         run: pip install -r sample-unity6/Tests/requirements-desktop.txt
+      - name: Start AltTester Desktop (AltServer) headless on port 13000
+        run: |
+          ALT_APP="${ALTTESTER_DESKTOP_APP:-/Applications/AltTester Desktop.app}"
+          if [ ! -d "$ALT_APP" ]; then
+            echo "AltTester Desktop not found at $ALT_APP; install it so the app and driver can connect to port 13000."
+            echo "See sample-unity6/Tests/README-ALTTESTER-MACOS.md"
+            exit 1
+          fi
+          EXE="$ALT_APP/Contents/MacOS/AltTester Desktop"
+          if [ ! -x "$EXE" ]; then
+            echo "AltTester Desktop executable not found or not executable: $EXE"
+            exit 1
+          fi
+          nohup "$EXE" -batchmode -port 13000 -nographics -logfile "${{ github.workspace }}/sample-unity6/Tests/alttester-desktop.log" &
+          sleep 5
+          if ! lsof -i :13000 >/dev/null 2>&1; then
+            echo "AltServer did not bind to port 13000 within 5s; check alttester-desktop.log"
+            exit 1
+          fi
+          echo "AltServer listening on port 13000"
       - name: Allow Unity app through macOS firewall for AltTester
         run: |
           APP_PATH="${{ github.workspace }}/sample-unity6/Tests/Sample Unity 6 macOS.app"
@@ -163,6 +183,11 @@ jobs:
           BROWSERSTACK_ACCESS_KEY: ${{ secrets.BROWSERSTACK_ACCESS_KEY }}
         working-directory: sample-unity6/Tests
         run: pytest -xs test/test_mac.py::MacTest
+      - name: Stop AltTester Desktop (AltServer)
+        if: always()
+        run: |
+          PID=$(lsof -ti :13000) || true
+          if [ -n "$PID" ]; then kill $PID 2>/dev/null || true; fi
       - name: Remove temporary keychain
         if: always()
         run: |