Setup tests

package.json

@@ -28,10 +28,12 @@
     "build-storybook": "build-storybook",
     "build:docs": "set DOCS=true && rollup -c",
     "dev:docs": "set DOCS=true && rollup -c -w",
+    "test": "jest",
     "prepublishOnly": "npm run build"
   },
   "devDependencies": {
     "@babel/core": "^7.12.10",
+    "@babel/preset-env": "^7.12.11",
     "@rollup/plugin-commonjs": "^17.0.0",
     "@rollup/plugin-json": "^4.1.0",
     "@rollup/plugin-node-resolve": "^11.0.0",
@@ -40,9 +42,11 @@
     "@storybook/addon-links": "^6.1.14",
     "@storybook/svelte": "^6.1.14",
     "babel-loader": "^8.2.2",
+    "jest": "^26.6.3",
     "lodash": "^4.17.20",
     "mdsvex": "^0.8.9",
     "rollup": "^2.3.4",
+    "rollup-plugin-babel": "^4.4.0",
     "rollup-plugin-css-only": "^3.1.0",
     "rollup-plugin-livereload": "^2.0.0",
     "rollup-plugin-svelte": "^7.0.0",