Added node modules for testing. Tweaked .gitignore

.gitignore

@@ -1,2 +1,3 @@
 
 node_modules/*
+package-lock.json

package.json

@@ -12,5 +12,10 @@
     "emulator"
   ],
   "author": "Bryan Miller",
-  "license": "ISC"
+  "license": "ISC",
+  "devDependencies": {
+    "chai": "^4.2.0",
+    "mocha": "^6.2.0",
+    "sinon": "^7.3.2"
+  }
 }