Fix nyc test code coverage reporting (#850)

Author: jacobdfriedmann

.babelrc

@@ -24,7 +24,10 @@
   ],
   "env": {
     "test": {
-      "plugins": ["istanbul"]
+      "plugins": [
+        "istanbul",
+        ["transform-es2015-modules-commonjs", { "loose": true }]
+      ]
     },
     "commonjs": {
       "plugins": [

package.json

@@ -14,7 +14,7 @@
     "clean": "rimraf lib dist es coverage",
     "lint": "eslint src test",
     "prepare": "npm run clean && npm run build",
-    "test": "cross-env BABEL_ENV=commonjs NODE_ENV=test mocha --compilers js:babel-register --recursive --require ./test/setup.js",
+    "test": "cross-env BABEL_ENV=test NODE_ENV=test mocha --compilers js:babel-register --recursive --require ./test/setup.js",
     "test:watch": "npm test -- --watch",
     "test:cov": "cross-env NODE_ENV=test nyc npm test",
     "coverage": "nyc report --reporter=text-lcov > coverage.lcov && codecov"
@@ -118,7 +118,14 @@
     ]
   },
   "nyc": {
+    "require": [
+      "babel-register"
+    ],
+    "all": "true",
     "sourceMap": false,
-    "instrument": false
+    "instrument": false,
+    "include": [
+      "src/**/*.js"
+    ]
   }
 }