feat: setup jest

package.json

@@ -35,6 +35,7 @@
     "@types/express": "^4.17.8",
     "@types/fs-extra": "^8.0.1",
     "@types/http-proxy": "^1.17.4",
+    "@types/jest": "^26.0.20",
     "@types/js-yaml": "^3.12.3",
     "@types/mocha": "^8.0.3",
     "@types/node": "^12.12.7",
@@ -55,6 +56,7 @@
     "eslint-config-prettier": "^6.0.0",
     "eslint-plugin-import": "^2.18.2",
     "eslint-plugin-prettier": "^3.1.0",
+    "jest": "^26.6.3",
     "leaked-handles": "^5.2.0",
     "mocha": "^8.1.2",
     "parcel-bundler": "^1.12.4",