👷 Add bats tests

.github/workflows/test_code.yaml

@@ -0,0 +1,19 @@
+---
+name: Test code
+
+# Run workflow on PRs and pushes to matching branches
+on:  # yamllint disable-line rule:truthy
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  test_bash:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: Install bats
+        run: apt install bats
+      - name: Run tests
+        run: bats tests