chore: add test config and instructions

README.md

@@ -23,13 +23,30 @@ $ pnpm i
 ## Commands
 
 | Command                       | Action                                         |
-| ------------------- | ---------------------------------------------- |
+| ----------------------------- | ---------------------------------------------- |
 | `pnpm run dev`                | start dev server                               |
 | `pnpm run build`              | generate static files to `dist` directory      |
 | `pnpm run deploy`             | upload to my server                            |
 | `pnpm run prep:now`           | back up and clear current `now page` constants |
 | `pnpm run patch:build:deploy` | increment version, build, then upload          |
 
+## Testing
+
+This project uses Vitest for unit tests. The test script is defined in `package.json` as `vitest run .`.
+
+Run tests locally with pnpm (recommended):
+
+```bash
+# install dependencies (if you haven't already)
+pnpm i
+
+# run tests once
+pnpm test
+
+# run Vitest in interactive/watch mode
+pnpm exec vitest
+```
+
 ## Deployment
 
 For the script `npm run deploy`, you need to add an environmental variable named HOST containing the IP address of the host server. This will scp the build files into the server.

vitest.config.ts

@@ -0,0 +1,14 @@
+import { defineConfig } from 'vitest/config'
+
+// Exclude generated files and heavy folders from the watcher to avoid
+// continuous re-runs when build output or other tools touch files.
+export default defineConfig({
+  test: {
+    globals: true,
+    environment: 'node',
+    exclude: ['dist/**', 'public/**', 'node_modules/**'],
+  },
+  watch: {
+    exclude: ['dist/**', 'public/**', 'node_modules/**', '.git/**'],
+  },
+})