Capture screenshots while running karma tests

karma.js

@@ -0,0 +1,88 @@
+const Server = require('karma').Server;
+const cfg = require('karma').config;
+const path = require('path');
+const karmaConfig = cfg.parseConfig(path.resolve('./karma.conf.js'));
+const server = new Server(karmaConfig, (exitCode) => {
+    console.log('Karma has exited with ' + exitCode);
+    process.exit(exitCode)
+});
+
+const fs = require('fs');
+const express = require('express');
+const bodyParser = require('body-parser');
+const cors = require('cors');
+const filenamifyUrl = require('filenamify-url');
+
+const app = express();
+app.use(cors());
+app.use(function(req, res, next) {
+    // IE9 doesn't set headers for cross-domain ajax requests
+    if(typeof(req.headers['content-type']) === 'undefined'){
+        req.headers['content-type'] = "application/json";
+    }
+    next();
+});
+app.use(
+    bodyParser.json({
+        limit: '15mb',
+        type: '*/*'
+    })
+);
+
+const prefix = 'data:image/png;base64,';
+
+const writeScreenshot = (buffer, body) => {
+    const filename = `${filenamifyUrl(
+        body.test.replace(/^\/tests\/reftests\//, '').replace(/\.html$/, ''),
+        {replacement: '-'}
+    )}!${body.platform.name}-${body.platform.version}.png`;
+
+    fs.writeFileSync(path.resolve(__dirname, './tests/results/', filename), buffer);
+};
+
+app.post('/screenshot', (req, res) => {
+    if (!req.body || !req.body.screenshot) {
+        return res.sendStatus(400);
+    }
+
+    const buffer = new Buffer(req.body.screenshot.substring(prefix.length), 'base64');
+    writeScreenshot(buffer, req.body);
+    return res.sendStatus(200);
+});
+
+const chunks = {};
+
+app.post('/screenshot/chunk', (req, res) => {
+    if (!req.body || !req.body.screenshot) {
+        return res.sendStatus(400);
+    }
+
+    const key = `${req.body.platform.name}-${req.body.platform.version}-${req.body.test
+        .replace(/^\/tests\/reftests\//, '')
+        .replace(/\.html$/, '')}`;
+    if (!Array.isArray(chunks[key])) {
+        chunks[key] = Array.from(Array(req.body.totalCount));
+    }
+
+    chunks[key][req.body.part] = req.body.screenshot;
+
+    if (chunks[key].every(s => typeof s === 'string')) {
+        const str = chunks[key].reduce((acc, s) => acc + s, '');
+        const buffer = new Buffer(str.substring(prefix.length), 'base64');
+        delete chunks[key];
+        writeScreenshot(buffer, req.body);
+    }
+
+    return res.sendStatus(200);
+});
+
+app.use((error, req, res, next) => {
+    console.error(error);
+    next();
+});
+
+const listener = app.listen(8081, () => {
+    server.start();
+});
+
+