Add GitHub Actions CI configuration

.github/workflows/test.yaml

@@ -0,0 +1,22 @@
+name: Run tests
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: cachix/install-nix-action@v26
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+
+      - uses: actions/checkout@v4
+
+      - run: |
+          nix develop -c composer install
+          nix develop -c ./run test

run.local

@@ -82,4 +82,8 @@ function publish {
   git stash pop
 }
 
+function test {
+  ./vendor/bin/phpunit "${@}"
+}
+
 # vim: ft=bash