[Backend Tester] Run Core ML tests in nightly CI

ghstack-source-id: 179408a
ghstack-comment-id: 3190288611
Pull-Request: #13446

Author: GregoryComer

.github/workflows/nightly.yml

@@ -58,3 +58,27 @@ jobs:
         EXIT_CODE=0
         .ci/scripts/test_backend_linux.sh "${{ matrix.suite }}" "${{ matrix.flow }}" "${RUNNER_ARTIFACT_DIR}" || EXIT_CODE=$?
         echo "Test run complete with exit code $EXIT_CODE."
+
+  backend-test-macos:
+    uses: pytorch/test-infra/.github/workflows/macos_job.yml@main
+    strategy:
+      fail-fast: false
+      matrix:
+        flow: [coreml, coreml_static_int8]
+        suite: [models, operators]
+    with:
+      ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}
+      runner: macos-latest-xlarge
+      python-version: 3.12
+      submodules: recursive
+      timeout: 90
+      upload-artifact: test-report-${{ matrix.flow }}-${{ matrix.suite }}
+      script: |
+        set -eux
+
+        # This is needed to get the prebuilt PyTorch wheel from S3
+        ${CONDA_RUN} --no-capture-output pip install awscli==1.37.21
+
+        EXIT_CODE=0
+        .ci/scripts/test_backend_macos.sh "${{ matrix.suite }}" "${{ matrix.flow }}" "${RUNNER_ARTIFACT_DIR}" || EXIT_CODE=$?
+        echo "Test run complete with exit code $EXIT_CODE."