Simplify test setup

In ember-electron 2.x, the `electron:test` command would build the Ember app into a temp location somewhere, so we'd have to jump through a bunch of hoops to pass that location to the Electron app so it could load the Ember app into the browser window.

In 3.x, we changed it so that the Ember app is always built into `electron-app/ember-test`, so we don't need to pass this extra information around at runtime. So we're now simplifying and better organizing the test infrastructure:

* Remove the code that handles passing the Ember app location through to the test main process
* Put the `electron-protocol-serve` setup code into a blueprint-generated utility function. This way the production and test versions of the app use the same code, and it's easier to see the correspondence between the two different usages
* Reorganize the test support code a bit for better flexibility -- rather than the test `index.js` just requiring a single file that runs all the test main process code, it imports some functions and calls them. This makes it a bit easier to read and understand, makes it easier to share code between the production and test main processes, and also allows more flexibility for users to customize, since the functionality that `ember-electron` supplies isn't all-or-nothing
* await the Ember Inspector installation before opening the browser window, to make sure we don't have a race condition. This should fix the intermittent failures we've seen in the test that verifies that we install Ember Inspector.
* Make end-to-end test more robust -- in this test we paste some code into the test `index.js` to verify some functionality, so rather than putting it at module scope, we put it in a function that we call so we don't have to worry about naming conflicts/duplicate imports between the blueprint-generated code and the test code we paste into the same file

Author: bendemboski

.eslintrc.js

@@ -63,10 +63,29 @@ module.exports = {
         'ember/avoid-leaking-state-in-ember-objects': 'off',
       })
     },
-    // forge template files
+    // test runner
     {
       files: [
-        'forge/files/**/*.js'
+        'lib/test-runner.js'
+      ],
+      env: {
+        browser: false,
+        node: true
+      },
+      plugins: ['node'],
+      rules: Object.assign({}, require('eslint-plugin-node').configs.recommended.rules, {
+        'node/no-missing-require': ['error', {
+          'allowModules': [
+            'ember-electron'
+          ],
+        }]
+      })
+    },
+    // Electon runtime files
+    {
+      files: [
+        'forge/files/**/*.js',
+        'lib/test-support/**/*.js'
       ],
       env: {
         browser: false,

blueprints/ember-electron/files/testem-electron.js

@@ -2,7 +2,7 @@ module.exports = {
   test_page: 'tests/index.html?hidepassed',
   disable_watching: true,
   launchers: {
-    Electron: require('ember-electron/lib/test-support/test-runner'),
+    Electron: require('ember-electron/lib/test-runner'),
   },
   launch_in_ci: [
     'Electron',

forge/files/src/index.js

@@ -1,32 +1,16 @@
 /* eslint-disable no-console */
-const { app, BrowserWindow, protocol } = require('electron');
-const { dirname, join, resolve } = require('path');
-const protocolServe = require('electron-protocol-serve');
-const isDev = require('electron-is-dev');
 const { default: installExtension, EMBER_INSPECTOR } = require('electron-devtools-installer');
+const { app, BrowserWindow } = require('electron');
+const path = require('path');
+const isDev = require('electron-is-dev');
+const setupServeProtocol = require('./setup-serve-protocol');
+
+const emberAppDir = path.resolve(__dirname, '..', 'ember-dist');
+const emberAppURL = 'serve://dist';
 
 let mainWindow = null;
 
-// Registering a protocol & schema to serve our Ember application
-if (typeof protocol.registerSchemesAsPrivileged === 'function') {
-  // Available in Electron >= 5
-  protocol.registerSchemesAsPrivileged([{
-    scheme: 'serve',
-    privileges: {
-      secure: true,
-      standard: true
-    }
-  }]);
-}
-else {
-  // For compatibility with Electron < 5
-  protocol.registerStandardSchemes(['serve'], { secure: true });
-}
-protocolServe({
-  cwd: join(__dirname || resolve(dirname('')), '..', 'ember-dist'),
-  app,
-  protocol,
-});
+setupServeProtocol(emberAppDir);
 
 // Uncomment the lines below to enable Electron's crash reporter
 // For more information, see http://electron.atom.io/docs/api/crash-reporter/
@@ -43,11 +27,18 @@ app.on('window-all-closed', () => {
   }
 });
 
-app.on('ready', () => {
+app.on('ready', async () => {
   if (isDev) {
-    require('devtron').install();
-    installExtension(EMBER_INSPECTOR)
-      .catch((err) => console.log('An error occurred: ', err));
+    try {
+      require('devtron').install();
+    } catch (err) {
+      console.log('Failed to install Devtrom: ', err);
+    }
+    try {
+      await installExtension(EMBER_INSPECTOR);
+    } catch (err) {
+      console.log('Failed to install Ember Inspector: ', err)
+    }
   }
 
   mainWindow = new BrowserWindow({
@@ -58,15 +49,13 @@ app.on('ready', () => {
   // If you want to open up dev tools programmatically, call
   // mainWindow.openDevTools();
 
-  const emberAppLocation = 'serve://dist';
-
-  // Load the ember application using our custom protocol/scheme
-  mainWindow.loadURL(emberAppLocation);
+  // Load the ember application
+  mainWindow.loadURL(emberAppURL);
 
   // If a loading operation goes wrong, we'll send Electron back to
   // Ember App entry point
   mainWindow.webContents.on('did-fail-load', () => {
-    mainWindow.loadURL(emberAppLocation);
+    mainWindow.loadURL(emberAppURL);
   });
 
   mainWindow.webContents.on('crashed', () => {

forge/files/src/setup-serve-protocol.js

@@ -0,0 +1,25 @@
+const { app, protocol } = require('electron');
+const protocolServe = require('electron-protocol-serve');
+const path = require('path');
+
+module.exports = function setupServeProtocol(emberAppDir) {
+  if (typeof protocol.registerSchemesAsPrivileged === 'function') {
+    protocol.registerSchemesAsPrivileged([{
+      scheme: 'serve',
+      privileges: {
+        secure: true,
+        standard: true,
+      },
+    }]);
+  }
+  else {
+    protocol.registerStandardSchemes(['serve'], { secure: true });
+  }
+  protocolServe({
+    cwd: emberAppDir,
+    app,
+    protocol,
+  });
+    
+  process.env.ELECTRON_PROTOCOL_SERVE_INDEX = path.join(emberAppDir, 'index.html');
+}

forge/files/tests/index.js

@@ -1,9 +1,31 @@
 const { default: installExtension, EMBER_INSPECTOR } = require('electron-devtools-installer');
+const path = require('path');
+const { app } = require('electron');
+const setupServeProtocol = require('../src/setup-serve-protocol');
+const { setupTestem, openTestWindow } = require('ember-electron/lib/test-support');
 
-require('electron').app.on('ready', function onReady() {
-  require('devtron').install();
-  installExtension(EMBER_INSPECTOR)
-    .catch((err) => console.log('An error occurred: ', err));
+const emberAppDir = path.resolve(__dirname, '..', 'ember-test');
+
+setupServeProtocol(emberAppDir);
+
+app.on('ready', async function onReady() {
+  try {
+    require('devtron').install();
+  } catch (err) {
+    console.log('Failed to install Devtrom: ', err);
+  }
+  try {
+    await installExtension(EMBER_INSPECTOR);
+  } catch (err) {
+    console.log('Failed to install Ember Inspector: ', err)
+  }
+
+  setupTestem();
+  openTestWindow();
 });
 
-require('ember-electron/lib/test-support/test-index');
+app.on('window-all-closed', function onWindowAllClosed() {
+  if (process.platform !== 'darwin') {
+    app.quit();
+  }
+});

lib/test-support/test-runner.js lib/test-runner.jslib/test-support/test-runner.js renamed to lib/test-runner.js

@@ -5,7 +5,7 @@
 // // testem.js
 // module.exports = {
 //   "launchers": {
-//     "Electron": require("ember-electron/lib/test-support/test-runner")
+//     "Electron": require("ember-electron/lib/test-runner")
 //   },
 //   "launch_in_ci": [
 //     "Electron"
@@ -21,50 +21,30 @@
 
 module.exports = {
   'exe': 'node',
-  'args': [__filename, '<cwd>', '<baseUrl>', '<testPage>', '<id>'],
+  // These arguments are used in `lib/test-support/index.js`, which is called
+  // from the test main process (via the blueprint-generated
+  // `electron-app/tests/index.js`)
+  'args': [__filename, '<testPage>', '<baseUrl>', '<id>'],
   'protocol': 'browser',
 };
 
 async function main() {
   const path = require('path');
-  const url = require('url');
-  const fileUrl = require('file-url');
   const treeKill = require('tree-kill');
   const { api } = require('ember-electron/lib/utils/forge-core');
   const { electronProjectPath } = require('ember-electron/lib/utils/build-paths');
 
-  let [, , emberAppDir, testemUrl, testPageUrl, id] = process.argv;
-
-  // The testPageUrl points to the testem server, so we need to turn it into a
-  // file URL and add the testem ID to the query params.
-  let {
-    pathname: testPagePath,
-    query: testPageQuery,
-  } = url.parse(testPageUrl, true);
-  let indexPath = path.resolve(emberAppDir, path.join.apply(null, testPagePath.split('/')));
-  let indexObj = url.parse(fileUrl(indexPath));
-  indexObj.query = testPageQuery;
-
-  // https://github.com/nodejs/node/issues/9500
-  for (let [ key, value ] of Object.entries(indexObj.query)) {
-    if ([ null, undefined, '' ].includes(value)) {
-      indexObj.query[key] = 'true';
-    }
-  }
-
-  // Set this so the script in shim-test-head.js can expose it to testem
-  indexObj.query.testemId = id;
-
-  let testUrl = url.format(indexObj);
+  let [, , testPageUrl, testemUrl, testemId] = process.argv;
 
   // Start electron
   let { pid } = await api.start({
     dir: path.join(process.cwd(), electronProjectPath),
     appPath: './tests',
     args: [
       '--', // needed because https://github.com/electron/electron/pull/13039
-      testUrl,
+      testPageUrl,
       testemUrl,
+      testemId
     ],
   });
   // Clean up when we're killed

lib/test-support/index.js

@@ -0,0 +1,63 @@
+const { session, BrowserWindow } = require('electron');
+const { URL } = require('url');
+
+// These are the command-line arguments passed to us by test-runner.js
+const [ , , , testPageURL, testemUrl, testemId ] = process.argv;
+
+// Set up communication with the testem server
+//
+// We broccoli'ed the src attribute in the script tag that loads testem.js to be
+// http://testemserver/testem.js, so it and every resource it loads will have a
+// base URL of http://testemserver. The test runner passes us the URL to the
+// actual testem server, so we can intercept any requests to http://testemserver
+// and redirect them to the actual testem server.
+function setupTestem() {
+  let { host: testemHost } = new URL(testemUrl);
+
+  session.defaultSession.webRequest.onBeforeRequest((details, callback) => {
+    let urlObj = new URL(details.url);
+    let { hostname } = urlObj;
+
+    if (hostname === 'testemserver') {
+      urlObj.host = testemHost;
+      callback({ redirectURL: urlObj.toString() });
+    } else {
+      callback({});
+    }
+  });
+}
+
+// Open the test window
+function openTestWindow() {
+  let window = new BrowserWindow({
+    width: 800,
+    height: 600,
+    webPreferences: {
+      backgroundThrottling: false,
+      nodeIntegration: true
+    }
+  });
+
+  delete window.module;
+
+  // Combine the test page URL with our root serve://dist URL
+  let url = new URL(testPageURL, 'serve://dist');
+
+  // We need to set this query param so the script in shim-test-head.js can
+  // expose it to testem to use when communicating with the testem server
+  url.searchParams.set('testemId', testemId);
+
+  // https://github.com/nodejs/node/issues/9500
+  for (let [ key, value ] of url.searchParams.entries()) {
+    if ([ null, undefined, '' ].includes(value)) {
+      url.searchParams.set(key, 'true');
+    }
+  }
+
+  window.loadURL(url.toString());
+}
+
+module.exports = {
+  setupTestem,
+  openTestWindow
+}