diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 8264dee..878820b 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -12,6 +12,8 @@ on:
 jobs:
   test:
     runs-on: ubuntu-22.04
+    permissions:
+      packages: write
     steps:
     - name: Checkout code
       uses: actions/checkout@v2
@@ -82,3 +84,9 @@ jobs:
         cat test-suite.log
         cat tests/*.log
         cat tests/unit-tests/*.log
+
+    - name: Push packages to buildcache and update index
+      if: ${{ !cancelled() }}
+      run: |
+        spack -e tests mirror set --push --oci-username ${{ github.actor }} --oci-password "${{ secrets.GITHUB_TOKEN }}" mochi-buildcache
+        spack -e tests buildcache push --base-image ubuntu:22.04 --unsigned --update-index mochi-buildcache
diff --git a/tests/spack.yaml b/tests/spack.yaml
index be9b2d9..eee8b4c 100644
--- a/tests/spack.yaml
+++ b/tests/spack.yaml
@@ -12,7 +12,7 @@ spack:
   - libtool
   - pkg-config
   - argobots
-  - mercury~boostsys ^libfabric fabrics=tcp,rxm
+  - mercury~checksum~boostsys ^libfabric fabrics=tcp,rxm
   concretizer:
     unify: true
     reuse: false
@@ -26,3 +26,5 @@ spack:
     test_cache: ~/.spack-ci/test_cache
     install_tree:
       root: ~/.spack-ci/install
+  mirrors:
+    mochi-buildcache: oci://ghcr.io/mochi-hpc/mochi-spack-buildcache