报错：No coverage information was collected, exit without writing coverage information

先贴出报错注意我的mocha单元测试均通过但是istanbul的测试覆盖率却无法生效。本地的test命令如下scripts: { test: istanbul cover ./node_modules/.bin/_mocha, },安装的istanbul的版本是v0.4.5, 官方安装的。解决方法重新安装istanbul版本是v1.0.0-alpha.2。安装完成之后命令行不需要改动即可跑。参考https://stackoverflow.com/questions/34538964/es6-react-istanbul-no-coverage-information-was-collected-exit-without-writing-c