sync-modules/test/index.js

automatically keep node_modules in sync with Git hooks

'use strict'

var assert = require('assert')
var childProcess = require('child_process')
var fs = require('fs')
var path = require('path')
var tmp = require('tmp')

function createTemporaryDirectory () {
  var directory

  directory = tmp.dirSync()

  return {
    exec: function (command) {
      return childProcess.execSync(command, {
        cwd: directory.name,
        encoding: 'utf8'
      })
    },

    exists: function (file) {
      try {
        fs.lstatSync(path.resolve(directory.name, file))
      } catch (exception) {
        return false
      }

      return true
    },

    toString: function () {
      return directory.name
    }
  }
}

describe('happy paths', function () {
  var d

  this.timeout(30 * 1000)

  before(function () {
    d = createTemporaryDirectory()
    console.log(`Running tests in temporary directory ${d}.`)

    d.exec(`
# Set up a sample project and install ourselves into it.
git init
npm init --yes
npm install --save ${__dirname}/..
git add package.json
git commit --message package.json

# Create a new branch called 'npm' that has the package 'npm' installed.
git checkout -b npm
npm install --save npm
git commit --all --message npm

# Create another branch named 'uninstalled' with the 'npm' package uninstalled.
git checkout -b uninstalled
npm uninstall --save npm
git commit --all --message uninstall
`)
  })

  beforeEach(function () {
    d.exec('git checkout -B test master')
  })

  it('installs additional packages after a checkout', function () {
    assert(!d.exists('node_modules/npm'))
    d.exec('git checkout npm')
    assert(d.exists('node_modules/npm'))
  })

  it('removes unused packages after a checkout', function () {
    d.exec('git checkout npm')
    assert(d.exists('node_modules/npm'))
    d.exec('git checkout master')
    assert(!d.exists('node_modules/npm'))
  })

  it('installs additional packages after a merge', function () {
    assert(!d.exists('node_modules/npm'))
    d.exec('git merge npm')
    assert(d.exists('node_modules/npm'))
  })

  it('removes additional packages after a merge', function () {
    d.exec('git checkout npm')
    assert(d.exists('node_modules/npm'))
    d.exec('git merge uninstalled')
    assert(!d.exists('node_modules/npm'))
  })

  it("performs checkout quickly when package.json doesn't change",
  function () {
    var time

    time = process.hrtime()
    d.exec('git checkout uninstalled')

    assert(process.hrtime(time)[1] < 5e8,
      '"git checkout" should take less than half a second.')
  })

  it("performs merge quickly when package.json doesn't change",
  function () {
    var time

    time = process.hrtime()
    d.exec('git merge uninstalled')

    assert(process.hrtime(time)[1] < 5e8,
      '"git merge" should take less than half a second.')
  })
})

describe('uninstallation', function () {
  var d

  before(function () {
    d = createTemporaryDirectory()
    console.log(`Running tests in temporary directory ${d}.`)
    d.exec('git init')
  })

  beforeEach(function () {
    d.exec(`
npm init --yes
npm install --save ${__dirname}/..
`)
  })

  it('removes Git hooks during uninstall', function () {
    assert(d.exists('.git/hooks/post-checkout'))
    assert(d.exists('.git/hooks/post-merge'))
    d.exec('npm uninstall --save sync-modules')
    assert(!d.exists('.git/hooks/post-checkout'))
    assert(!d.exists('.git/hooks/post-merge'))
  })
})

describe('sad paths', function () {
  var d

  beforeEach(function () {
    d = createTemporaryDirectory()
    console.log(`Running tests in temporary directory ${d}.`)
    d.exec('git init')
  })

  it('refuses to install if there is already a post-checkout hook',
  function () {
    d.exec('touch .git/hooks/post-checkout')

    assert.throws(function () {
      d.exec('npm install --save ${__dirname}/..')
    })
  })

  it('refuses to install if there is already a post-merge hook',
  function () {
    d.exec('touch .git/hooks/post-merge')

    assert.throws(function () {
      d.exec('npm install --save ${__dirname}/..')
    })
  })
})