已經解決，npm install grunt-mocha --save-dev

D:\grunt-in-action\grunt-yo-webapp>npm?install?grunt-mocha
npm?WARN?package.json?grunt-yo-webapp@?No?description
npm?WARN?package.json?grunt-yo-webapp@?No?repository?field.
npm?WARN?package.json?grunt-yo-webapp@?No?README?data
-\/-\|/-\|/-\|/-\|/-\|/--\|/\|/|\|/-\|/-|/-\|/-\|/\|/-|-\|/-|/-\|\|/-|/-|/-\|/-\/-\|/-\|/-\|/-|/-\|/-\|/-\-\|/-\|-\|/\/\|/-\/-\|\/-\|-|/-\|/-\|/-\|/-|/-\/\|-\|/-\|-\|/-\|/-\|/\-\|-\|/-\|/-\|/\/-\|-\|
>[email protected]?install?D:\grunt-in-action\grunt-yo-webapp\node_modules\grunt-mocha\node_modules\grunt-lib-phantomjs\node_modules\phantomjs
>?node?install.js

Downloading?https://bitbucket.org/ariya/phantomjs/downloads/phantomjs-1.9.8-windows.zip
Saving?to?C:\Users\LIJIE\AppData\Local\Temp\phantomjs\phantomjs-1.9.8-windows.zip
Receiving...

Error?making?request.
Error:?connect?ETIMEDOUT
????at?exports._errnoException?(util.js:746:11)
????at?TCPConnectWrap.afterConnect?[as?oncomplete]?(net.js:983:19)

Please?report?this?full?log?at?https://github.com/Medium/phantomjs
npm?ERR!?Windows_NT?6.2.9200
npm?ERR!?argv?"C:\\Program?Files\\nodejs\\\\node.exe"?"C:\\Program?Files\\nodejs\\node_modules\\npm\\bin\\npm-cli.js"?"install"?"grunt-mocha"
npm?ERR!?node?v0.12.1
npm?ERR!?npm??v2.5.1
npm?ERR!?code?ELIFECYCLE

[email protected]?install:?`node?install.js`
npm?ERR!?Exit?status?1
npm?ERR!?
[email protected]?install?script?'node?install.js'.
npm?ERR!?This?is?most?likely?a?problem?with?the?phantomjs?package,
npm?ERR!?not?with?npm?itself.
npm?ERR!?Tell?the?author?that?this?fails?on?your?system:
npm?ERR!?????node?install.js
npm?ERR!?You?can?get?their?info?via:
npm?ERR!?????npm?owner?ls?phantomjs
npm?ERR!?There?is?likely?additional?logging?output?above.

npm?ERR!?Please?include?the?following?file?with?any?support?request:
npm?ERR!?????D:\grunt-in-action\grunt-yo-webapp\npm-debug.log