No issue: add Android Emulator action for contributor PRs (#18901)

.github/workflows/build-contributor-pr.yml

@@ -105,3 +105,30 @@ jobs:
           name: lintDebug report
           path: app/build/reports/lint-results-debug.html
 
+  run-ui:
+    runs-on: macos-latest
+    if: github.event.pull_request.head.repo.full_name != github.repository && github.actor != 'MickeyMoz'
+
+    timeout-minutes: 60
+    strategy:
+      matrix:
+        api-level: [28]
+        target: [google_apis]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Run subset of UI Tests
+        uses: reactivecircus/android-emulator-runner@v2
+        with:
+          api-level: ${{ matrix.api-level }}
+          target: ${{ matrix.target }}
+          arch: x86_64
+          profile: pixel_3a
+          script:
+            "./gradlew connectedDebugAndroidTest -Pandroid.testInstrumentationRunnerArguments.class=\
+            org.mozilla.fenix.ui.NavigationToolbarTest#visitURLTest"
+      - name: Upload Test Artifacts
+        uses: actions/upload-artifact@v2
+        with:
+          name: test-report
+          path: app/build/reports