[Tests] fix unit-test script

Author: ljharb

package.json

@@ -8,8 +8,8 @@
     "coveralls": "cat ./reports/coverage/lcov.info | coveralls",
     "lint": "eslint ./",
     "pretest": "npm run lint",
-    "test": "npm run unit-test",
-    "unit-test": "istanbul cover --dir reports/coverage node_modules/mocha/bin/_mocha tests/**/*.js -- --reporter dot"
+    "test": "npm run unit-test tests/**/*.js",
+    "unit-test": "istanbul cover --dir reports/coverage node_modules/mocha/bin/_mocha -- --reporter dot"
   },
   "files": [
     "LICENSE",