如何在凉亭中安装包的devDependencies？

Question

如果我重新安装一个软件包（例如Polymer，但它可能是_anything）：

:after

树中缺少devDependencies：

merc@mercs-thinkpad:~$ mkdir tt
merc@mercs-thinkpad:~$ cd tt
merc@mercs-thinkpad:~/tt$ bower install polymer
bower cached        https://github.com/Polymer/polymer.git#1.6.0
bower validate      1.6.0 against https://github.com/Polymer/polymer.git#*
bower cached        https://github.com/Polymer/webcomponentsjs.git#0.7.22
bower validate      0.7.22 against https://github.com/Polymer/webcomponentsjs.git#^0.7.20
bower install       polymer#1.6.0
bower install       webcomponentsjs#0.7.22

polymer#1.6.0 bower_components/polymer
└── webcomponentsjs#0.7.22

webcomponentsjs#0.7.22 bower_components/webcomponentsjs
merc@mercs-thinkpad:~/tt$ 

然而，Polymer显然有一个devDependency：

merc@mercs-thinkpad:~/tt$ ls -l bower_components/
total 8
drwxrwxr-x 2 merc merc 4096 Jul 16 21:37 polymer
drwxrwxr-x 2 merc merc 4096 Jul 16 21:37 webcomponentsjs
merc@mercs-thinkpad:~/tt$ 

凉亭页面说：

merc@mercs-thinkpad:~/tt$ cat bower_components/polymer/bower.json 
...
  "dependencies": {
    "webcomponentsjs": "^0.7.20"
  },
  "devDependencies": {
    "web-component-tester": "*"
  },

这似乎意味着始终安装devDependencies，除非您另行指定。

但是，我似乎找不到实际使用bower为任何包安装devDependencies的方法。

我错过了什么？