diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index 753d304..6dac74e 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -13,7 +13,9 @@ jobs:
     runs-on: macos-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
+        with:
+          lfs: true
 
       - name: Make install script executable
         run: chmod +x ./install-forefire-osx.sh
@@ -23,3 +25,18 @@ jobs:
 
       - name: Check ForeFire version
         run: ./bin/forefire -v
+
+      - name: Install Python test dependencies
+        run: pip3 install --break-system-packages lxml xarray netCDF4
+
+      - name: Add Build/Runtime Diagnostics
+        run: |
+          echo "--- Input data.nc Info ---"
+          ls -lh tests/runff/data.nc
+          brew install netcdf
+          ncdump -k tests/runff/data.nc || echo "Could not check data.nc format"
+
+      - name: Run 'runff' Test Script
+        run: |
+          cd tests/runff
+          bash ff-run.bash
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