我没有伊斯坦布尔和摩卡咖啡的代码覆盖率统计信息。

我已经按如下方式安装了伊斯坦布尔：

$ npm install --save-dev nyc

然后我将package.json“ scripts”修改为：

"scripts": {
  "test": "nyc mocha test/descriptor-util-test.js"
}

但是，当我运行此命令时：

$ npm test

然后我得到这个结果：

<snIP>
sensitive property
  ✓ should succeed with sensitive string
  ✓ should succeed with insensitive string
  ✓ should succeed with sensitive array
  ✓ should succeed with insensitive array
  ✓ should succeed with sensitive object (all properties)
  ✓ should succeed with object with sensitive and insensitive properties
  ✓ should succeed with map-inline object with sensitive and insensitive properties
  ✓ should succeed with map-reference object with sensitive and insensitive properties
method example
  ✓ should succeed with a valid descriptor

85 passing (62ms)

----------|---------|----------|---------|---------|-------------------
File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
----------|---------|----------|---------|---------|-------------------
All files |       0 |        0 |       0 |       0 |                   
----------|---------|----------|---------|---------|-------------------

因此，没有代码覆盖率统计信息：（

关于什么是错的任何想法？谢谢！