Download browser at start of test

bin/download_browser.js

@@ -0,0 +1,23 @@
+/**
+ * Copyright (c) 2020 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+const playwright = require('playwright-core');
+const fs = require('fs');
+
+// Default to chromium
+let browserType = playwright['chromium'];
+const index = process.argv.indexOf('--browser');
+if (index !== -1 && process.argv.length > index + 1 && typeof process.argv[index + 1] === 'string') {
+  const string = process.argv[index + 1];
+  if (string === 'firefox' || string === 'webkit') {
+    browserType = playwright[string];
+  }
+}
+
+const exists = fs.existsSync(browserType.executablePath());
+if (!exists) {
+  console.log(`Downloading ${browserType.name()}`);
+  browserType.downloadBrowserIfNeeded().then(() => process.exit(0));
+}