Integration test: screenshot compare ignoring transparency

package.json

@@ -66,6 +66,7 @@
     "nodemon": "^1.10.2",
     "open": "0.0.5",
     "plist": "^2.0.1",
+    "pngjs": "^3.0.0",
     "rimraf": "^2.5.2",
     "run-series": "^1.1.4",
     "spectron": "^3.3.0",

test/index.js

@@ -15,9 +15,10 @@ test('app runs', function (t) {
 })
 
 require('./test-torrent-list')
-// require('./test-add-torrent')
+require('./test-add-torrent')
-// require('./test-video')
+require('./test-video')
 
+// TODO:
 // require('./test-audio')
 // require('./test-cast')
 // require('./test-prefs')

test/setup.js

@@ -2,6 +2,7 @@ const path = require('path')
 const Application = require('spectron').Application
 const fs = require('fs-extra')
 const parseTorrent = require('parse-torrent')
+const PNG = require('pngjs').PNG
 const config = require('./config')
 
 module.exports = {
@@ -78,7 +79,7 @@ function screenshotCreateOrCompare (app, t, name) {
       console.log('Saving screenshot ' + ssPath)
       fs.writeFileSync(ssPath, buffer)
     } else {
-      const match = Buffer.compare(buffer, ssBuf) === 0
+      const match = compareIgnoringTransparency(buffer, ssBuf)
       t.ok(match, 'screenshot comparison ' + name)
       if (!match) {
         const ssFailedPath = path.join(ssDir, name + '-failed.png')
@@ -89,6 +90,30 @@ function screenshotCreateOrCompare (app, t, name) {
   })
 }
 
+// Compares two PNGs, ignoring any transparent regions in bufExpected.
+// Returns true if they match.
+function compareIgnoringTransparency (bufActual, bufExpected) {
+  // Common case: exact byte-for-byte match
+  if (Buffer.compare(bufActual, bufExpected) === 0) return true
+
+  // Otherwise, compare pixel by pixel
+  const pngA = PNG.sync.read(bufActual)
+  const pngE = PNG.sync.read(bufExpected)
+  if (pngA.width !== pngE.width || pngA.height !== pngE.height) return false
+  const w = pngA.width
+  const h = pngE.height
+  const da = pngA.data
+  const de = pngE.data
+  for (let y = 0; y < h; y++) {
+    for (let x = 0; x < w; x++) {
+      const i = (y * w + x) * 4
+      if (de[i + 3] === 0) continue // Skip transparent pixels
+      if (da[i] !== de[i] || da[i + 1] !== de[i + 1] || da[i + 2] !== de[i + 2]) return false
+    }
+  }
+  return true
+}
+
 // Resets the test directory, containing config.json, torrents, downloads, etc
 function resetTestDataDir () {
   fs.removeSync(config.TEST_DIR)

test/test-video.js

@@ -9,7 +9,7 @@ test('basic-streaming', function (t) {
   setup.waitForLoad(app, t, {online: true})
     .then(() => app.client.waitUntilTextExists('.torrent-list', 'Big Buck Bunny'))
     // Play Big Buck Bunny. Wait for it to start streaming.
-    .then(() => app.client.moveToObject('.torrent.bbb'))
+    .then(() => app.client.moveToObject('.torrent'))
     .then(() => setup.wait())
     .then(() => app.client.click('.icon.play'))
     .then(() => setup.wait(10e3))
@@ -23,6 +23,8 @@ test('basic-streaming', function (t) {
     .then(() => app.webContents.executeJavaScript('dispatch("escapeBack")'))
     .then(() => setup.wait())
     // Delete Big Buck Bunny
+    .then(() => app.client.moveToObject('.torrent'))
+    .then(() => setup.wait())
     .then(() => app.client.click('.icon.delete'))
     .then(() => setup.wait())
     .then(() => app.client.click('.control.ok'))