test(E2E): End-to-end tests for script tag (#633)

fix #621

package.json

@@ -28,6 +28,7 @@
     "test:unit:ci": "jest --ci --runInBand --collectCoverage --reporters=default --reporters=jest-junit && codecov",
     "test:e2e": "",
     "test:e2e:ci": "start-server-and-test start http://localhost:5000 cy:run:ci",
+    "test:e2e:scriptTag": "cross-env START_SERVER=true start-server-and-test build:package http-get://localhost:5000/index.umd.js cy:run",
     "staticDeploy": "./generateStaticSite.sh",
     "docs:publish": "./publishStaticSite.sh",
     "start": "yarn run dev",
@@ -154,6 +155,7 @@
     "rollup-plugin-node-resolve": "^5.0.2",
     "rollup-plugin-peer-deps-external": "^2.2.0",
     "rollup-plugin-postcss": "^2.0.3",
+    "rollup-plugin-serve": "^1.0.1",
     "rollup-plugin-url": "^2.2.2",
     "semantic-release": "15.13.x",
     "start-server-and-test": "^1.9.1",