workflow: demonstrate and test ccache configuration

Add steps for demonstrating and testing the ccache configuration
performed in the action.

Signed-off-by: Henrik Brix Andersen <henrik@brixandersen.dk>

Author: henrikbrixandersen

.github/workflows/test.yaml

@@ -40,6 +40,19 @@ jobs:
           west-group-filter: -tools,-bootloader,-babblesim
           west-project-filter: -nrf_hw_models
 
+      - name: Restore ccache
+        id: ccache-restore
+        uses: actions/cache/restore@v4
+        with:
+          path: ${{ env.CCACHE_DIR }}
+          key: ${{ runner.os }}-ccache
+
+      - name: Set up ccache
+        run: |
+          mkdir -p ${{ env.{CCACHE_DIR }}
+          ccache -p
+          ccache -z -s -vv
+
       - name: Build firmware
         working-directory: zephyr
         shell: bash
@@ -65,3 +78,13 @@ jobs:
           PLATFORMS_FLAGS+="-p qemu_x86_64"
 
           ./scripts/twister --force-color --inline-logs -T samples/hello_world -v $PLATFORMS_FLAGS $EXTRA_TWISTER_FLAGS
+
+      - name: Print ccache stats
+        run: |
+          ccache -s -vv
+
+      - name: Save ccache
+        uses: actions/cache/save@v4
+        with:
+          path: ${{ env.CCACHE_DIR }}
+          key: ${{ steps.ccache-restore.outputs.cache-primary-key }}