chore: prepare vitest for astro

Author: kyoh86

package.json

@@ -16,7 +16,9 @@
     "lint:fix": "eslint --cache --fix src",
     "prettier:check": "prettier --cache --check --plugin-search-dir=. src",
     "prettier:fix": "prettier --cache --write --plugin-search-dir=. src",
-    "preinstall": "npx only-allow pnpm"
+    "preinstall": "npx only-allow pnpm",
+    "test": "pnpm '/^test:.*/'",
+    "test:unit": "vitest"
   },
   "dependencies": {
     "@astrojs/check": "^0.9.4",
@@ -30,7 +32,8 @@
     "dayjs": "^1.11.13",
     "sharp": "^0.33.5",
     "svelte": "^4.2.19",
-    "svelte-chartjs": "^3.1.5"
+    "svelte-chartjs": "^3.1.5",
+    "vitest": "^2.1.6"
   },
   "devDependencies": {
     "@astrojs/ts-plugin": "^1.10.4",