As evidenced by failed builds on develop, the latest version of npm (5.0.0, just released) fails to install our current package.json because of problems with node-sass and phantomjs-compiled.

+ /var/lib/workspace/workspace/test_plugin_pull_request/database/postgresql/label/fast/ruby/2.4/foreman/node_modules/.bin/npm install
npm WARN deprecated jquery-flot@0.8.3: flot has been abandoned
npm WARN deprecated minimatch@2.0.10: Please update to minimatch 3.0.2 or higher to avoid a RegExp DoS issue
npm WARN deprecated babel-preset-latest@6.16.0:   preset-latest accomplishes the same task as babel-preset-env.   Please install it with 'npm install babel-preset-env --save-dev'. '{ "presets": ["latest"] }' to '{ "presets": ["env"] }'. For more info, please check the docs: http://babeljs.io/docs/plugins/preset-env . And let us know how you're liking Babel at @babeljs on 
npm WARN prefer global marked@0.3.6 should be installed with -g

> phantomjs-prebuilt@2.1.14 install /var/lib/workspace/workspace/test_plugin_pull_request/database/postgresql/label/fast/ruby/2.4/foreman/node_modules/phantomjs-prebuilt
> node install.js

module.js:471
    throw err;
    ^

Error: Cannot find module 'core-util-is'
    at Function.Module._resolveFilename (module.js:469:15)
    at Function.Module._load (module.js:417:25)
    at Module.require (module.js:497:17)
    at require (internal/module.js:20:19)
    at Object.<anonymous> (/var/lib/workspace/workspace/test_plugin_pull_request/database/postgresql/label/fast/ruby/2.4/foreman/node_modules/readable-stream/lib/_stream_readable.js:41:12)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)

> node-sass@4.5.3 install /var/lib/workspace/workspace/test_plugin_pull_request/database/postgresql/label/fast/ruby/2.4/foreman/node_modules/node-sass
> node scripts/install.js

module.js:471
    throw err;
    ^

Error: Cannot find module 'tough-cookie'
    at Function.Module._resolveFilename (module.js:469:15)
    at Function.Module._load (module.js:417:25)
    at Module.require (module.js:497:17)
    at require (internal/module.js:20:19)
    at Object.<anonymous> (/var/lib/workspace/workspace/test_plugin_pull_request/database/postgresql/label/fast/ruby/2.4/foreman/node_modules/request/lib/cookies.js:3:13)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: phantomjs-prebuilt@2.1.14 (node_modules/phantomjs-prebuilt):
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: phantomjs-prebuilt@2.1.14 install: `node install.js`
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: Exit status 1

npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! node-sass@4.5.3 install: `node scripts/install.js`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the node-sass@4.5.3 install script.

(http://ci.theforeman.org/job/test_plugin_pull_request/3775/)

To bring tests back to green a quick solution is to limit npm tests to 4.x