setup tests

package.json

@@ -4,7 +4,7 @@
   "description": "rrweb's component to take a snapshot of DOM, aka DOM serializer",
   "main": "index.js",
   "scripts": {
-    "test": "mocha -r ts-node/register src/**/*.test.ts"
+    "test": "TS_NODE_FILES=true mocha -r ts-node/register test/**/*.ts"
   },
   "repository": {
     "type": "git",
@@ -23,9 +23,13 @@
   "homepage": "https://github.com/rrweb-io/rrweb-snapshot#readme",
   "devDependencies": {
     "@types/chai": "^4.1.4",
+    "@types/jsdom": "^11.12.0",
     "@types/mocha": "^5.2.5",
+    "@types/node": "^10.11.3",
     "chai": "^4.1.2",
+    "jsdom": "^12.1.0",
     "mocha": "^5.2.0",
+    "mocha-jsdom": "^2.0.0",
     "ts-node": "^7.0.1",
     "tslint": "^4.5.1",
     "typescript": "^3.0.3"