Classes. Who doesn't like classes?

Also include a test.

Electron-mocha sets up an Electron instance and runs Mocha within
it. One oddity is that it consumes the ready event before running the
Mocha scripts, so that has to be faked (or assumed) within the test.

index.js

@@ -1,47 +1,60 @@
 'use strict'
-const {app, BrowserWindow} = require('electron')
 const yargs = require('yargs')
 const temp = require('temp')
 const path = require('path')
+const {app, BrowserWindow} = require('electron')
 
-process.on('uncaughtException', function (err) {
-  console.error(err)
-  app.quit()
-})
-
-var win, filename, url
+class Scanner {
+  run (url, cb) {
+    this.url = url
+    this.cb = cb
+    process.on('uncaughtException', function (err) {
+      console.error(err)
+      app.exit(1)
+    })
+    app.once('ready', () => this.onReady())
+  }
 
-function onReady () {
-  const options = { frame: false, height: 768, width: 1024, x: 0, y: 0, show: false }
-  win = new BrowserWindow(options)
-  win.webContents.once('did-stop-loading', grabPage)
-  win.loadURL(url)
-}
+  onReady () {
+    const options = { frame: true, height: 768, width: 1024, x: 0, y: 0, show: false }
+    this.win = new BrowserWindow(options)
+    this.win.webContents.once('did-stop-loading', () => this.grabPage())
+    this.win.loadURL(this.url)
+  }
 
-function grabPage () {
-  temp.track()
-  const dir = temp.mkdirSync('scanner')
-  filename = path.join(dir, 'page.html')
-  console.log(`Saving to ${filename}`)
-  win.webContents.savePage(filename, 'HTMLOnly', scanPage)
-}
+  grabPage () {
+    temp.track()
+    const dir = temp.mkdirSync('scanner')
+    this.filename = path.join(dir, 'page.html')
+    console.log(`Saving to ${this.filename}`)
+    this.win.webContents.savePage(this.filename, 'HTMLOnly', () => this.scanPage())
+  }
 
-function scanPage (error) {
-  // Do the scan here, HTML source is in filename
-  app.quit()
-  if (error) {
-    console.error(error)
-    process.exit(-1)
+  scanPage (error) {
+    // Do the scan here, HTML source is in this.filename
+    if (this.cb) {
+      this.cb(error) // Assume caller will quit the app.
+    } else {
+      if (error) {
+        console.error(error)
+        app.exit(1)
+      } else {
+        app.quit()
+      }
+    }
   }
 }
 
-const argv = yargs
-  .usage('Usage: $0 URL')
-  .demand(1)
-  .strict()
-  .version()
-  .help('h')
-  .argv
-
-url = argv._[0]
-app.once('ready', onReady)
+if (!module.parent || module.parent.id === '.') {
+  const argv = yargs
+        .usage('Usage: $0 URL')
+        .demand(1)
+        .strict()
+        .version()
+        .help('h')
+        .argv
+  const s = new Scanner()
+  s.run(argv._[0])
+} else {
+  module.exports = Scanner
+}

package.json

@@ -4,15 +4,20 @@
   "description": "Advise on what's adblocking you.",
   "main": "index.js",
   "scripts": {
-    "test": "mocha"
+    "test": "electron-mocha",
+    "testmon": "nodemon --exec '(electron-mocha && growlnotify -n nodemon --image ~/green.png -m good) || (growlnotify -n nodemon --image ~/red.png -m crash && exit 1)'"
   },
   "bin": {
     "scan": "./bin/scan"
   },
   "author": "",
   "license": "ISC",
   "devDependencies": {
-    "mocha": "^2.5.3"
+    "chai": "^3.5.0",
+    "electron-mocha": "^2.3.0",
+    "express": "^4.14.0",
+    "mocha": "^2.5.3",
+    "nodemon": "^1.9.2"
   },
   "dependencies": {
     "electron-prebuilt": "^1.2.6",

test/test-index.js

@@ -0,0 +1,43 @@
+/* global describe, before, after, it */
+const expect = require('chai').expect
+const express = require('express')
+const temp = require('temp')
+const path = require('path')
+const sinon = require('sinon')
+const Scanner = require('..')
+const fs = require('fs')
+const {app} = require('electron')
+
+describe('Scanner', function () {
+  before(function (done) {
+    const app = express()
+    app.route('/').get((req, res) => {
+      res.send('Yeah')
+    })
+    this.server = app.listen(() => {
+      this.url = `http://localhost:${this.server.address().port}`
+      done()
+    })
+  })
+
+  after(function () {
+    this.server.close()
+  })
+
+  it('can render and obtain HTML', sinon.test(function (done) {
+    temp.track()
+    const test_dir = temp.mkdirSync('scanner-test')
+    this.stub(temp, 'mkdirSync', () => test_dir) // Sub in our own dir
+
+    const s = new Scanner()
+    const finish = function (error) {
+      expect(error).to.be.nil
+      const page_file = path.join(test_dir, 'page.html')
+      const file_contents = fs.readFileSync(page_file)
+      expect(file_contents.toString()).to.equal('Yeah')
+      done()
+    }
+    s.run(this.url, finish)
+    s.onReady() // Because electron-mocha already consumed the ready event
+  }))
+})