ci: Add build tests for RNTester (#33033)

Summary:
Add 4 new jobs to CI in order to test RNTester builds on both Android and iOS using Hermes and JSC

Closes https://github.com/facebook/react-native/issues/32676

## Changelog

[General] [Added] - Add build tests for RNTester to CircleCI

Pull Request resolved: https://github.com/facebook/react-native/pull/33033

Test Plan: Make sure builds are working as expected and CI is green

Reviewed By: lunaleaps

Differential Revision: D33982864

Pulled By: philIip

fbshipit-source-id: 00b2116be1b6484324e8162cc691b1d0863d282d

.circleci/config.yml

@@ -588,6 +588,37 @@ jobs:
           name: Build the template application
           command: cd template/android/ && ./gradlew assembleDebug
 
+  # -------------------------
+  #    JOBS: Test Android RNTester
+  # -------------------------
+  test_android_rntester:
+    executor: reactnativeandroid
+    parameters:
+      use_hermes:
+          type: boolean
+          default: false
+    steps:
+      - checkout
+      - run_yarn
+
+      - run:
+          name: Generate artifacts for Maven
+          command: ./gradlew :ReactAndroid:installArchives
+
+      - when:
+          condition: << parameters.use_hermes >>
+          steps:
+            - run:
+                name: Build RNTester with Hermes
+                command: ./gradlew :packages:rn-tester:android:app:assembleHermesDebug
+      - when:
+          condition:
+            not: << parameters.use_hermes >>
+          steps:
+            - run:
+                name: Build RNTester with JSC
+                command: ./gradlew :packages:rn-tester:android:app:assembleJscDebug
+
   # -------------------------
   #    JOBS: Test iOS Template
   # -------------------------
@@ -621,6 +652,40 @@ jobs:
               -scheme $PROJECT_NAME \
               -sdk iphonesimulator
 
+  # -------------------------
+  #    JOBS: Test iOS RNTester
+  # -------------------------
+  test_ios_rntester:
+    executor: reactnativeios
+    parameters:
+      use_hermes:
+          type: boolean
+          default: false
+    steps:
+      - checkout
+      - run_yarn
+
+      - when:
+          condition: << parameters.use_hermes >>
+          steps:
+            - run:
+                name: Set USE_HERMES=1
+                command: echo "export USE_HERMES=1" >> $BASH_ENV
+
+      - run:
+          name: Install CocoaPods dependencies
+          command: |
+            rm -rf packages/rn-tester/Pods
+            cd packages/rn-tester && bundle exec pod install
+
+      - run:
+          name: Build RNTester
+          command: |
+            xcodebuild build \
+              -workspace packages/rn-tester/RNTesterPods.xcworkspace \
+              -scheme RNTester \
+              -sdk iphonesimulator
+
   # -------------------------
   #    JOBS: Windows
   # -------------------------
@@ -885,12 +950,34 @@ workflows:
           filters:
             branches:
               ignore: gh-pages
+      - test_android_rntester:
+          name: test_android_rntester_hermes
+          use_hermes: true
+          filters:
+            branches:
+              ignore: gh-pages
+      - test_android_rntester:
+          name: test_android_rntester_jsc
+          filters:
+            branches:
+              ignore: gh-pages
       - test_ios_template:
           requires:
             - build_npm_package
           filters:
             branches:
               ignore: gh-pages
+      - test_ios_rntester:
+          name: test_ios_rntester_hermes
+          use_hermes: true
+          filters:
+            branches:
+              ignore: gh-pages
+      - test_ios_rntester:
+          name: test_ios_rntester_jsc
+          filters:
+            branches:
+              ignore: gh-pages
       - test_ios:
           name: test_ios_unit_jsc
           run_unit_tests: true