ci: Add template test

.github/workflows/ci.yml

@@ -4,15 +4,36 @@ name: Nix CI
 on:
   push:
     branches: main
+  pull_request:
   workflow_dispatch:
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
   cancel-in-progress: true
 
 jobs:
-  build:
-    name: Build and cache Lean
+  test:
+    name: Test LSpec template
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: DeterminateSystems/nix-installer-action@main
+      - uses: cachix/cachix-action@v14
+        with:
+          name: argumentcomputer
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+      - name: Patch flake.nix with current commit
+        run: |
+          sed -i 's|github:argumentcomputer/lean4-nix|path:../../|g' flake.nix
+        working-directory : ${{ github.workspace }}/templates/lake-project
+      - run: nix build .#default .#lspec
+        working-directory : ${{ github.workspace }}/templates/lake-project
+      - run: nix run .#lspec
+        working-directory : ${{ github.workspace }}/templates/lake-project
+
+  cache:
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+    name: Build and cache Lean artifacts
     runs-on: warp-ubuntu-latest-x64-16x
     steps:
       - uses: actions/checkout@v4