enable macos unit tests

PiperOrigin-RevId: 706759813

.github/workflows/nightly_unittests.yml

@@ -20,3 +20,4 @@ jobs:
     uses: ./.github/workflows/unittests_python.yml
     with:
       trigger-sha: ${{ github.sha }}
+      run-on-macos: true

.github/workflows/unittests_python.yml

@@ -14,14 +14,31 @@ on:
       trigger-sha:
         required: true
         type: string
-
+      run-on-macos:
+        type: boolean
+        default: true
 jobs:
+  matrix-prep:
+    runs-on: ubuntu-latest
+    outputs:
+      os: ${{ steps.set-matrix.outputs.matrix_os }}
+    steps:
+      - id: set-matrix
+        run: |
+          os=("Linux_runner_8_core")
+          if [[ "${{ inputs.run-on-macos }}" == "true" ]]; then
+            os+=("macos-latest" "macos-13")
+          fi
+          os=$(jq -c -n '$ARGS.positional' --args "${os[@]}")
+          echo "os: ${os}"
+          echo "matrix_os=${os}" >> $GITHUB_OUTPUT
   test:
+    needs: matrix-prep
     strategy:
       matrix:
         python-version: ["3.10", "3.11"]
-    runs-on:
-      labels: Linux_runner_8_core
+        os: ${{ fromJson(needs.matrix-prep.outputs.matrix_os) }}
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v3
         with: