Support PhantomJS.

lib/src/runner/browser/phantom_js.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library test.runner.browser.phantom_js;
+
+import 'dart:async';
+import 'dart:io';
+
+import 'package:path/path.dart' as p;
+
+import '../../util/io.dart';
+import 'browser.dart';
+
+/// The PhantomJS script that opens the host page.
+final _script = """
+var system = require('system');
+var page = require('webpage').create();
+
+// Pipe browser messages to the process's stdout. This isn't used by default,
+// but it can be useful for debugging.
+page.onConsoleMessage = function(message) {
+  console.log(message);
+}
+
+page.open(system.args[1], function(status) {
+  if (status !== "success") phantom.exit(1);
+});
+""";
+
+/// A class for running an instance of PhantomJS.
+///
+/// Any errors starting or running the process are reported through [onExit].
+class PhantomJS implements Browser {
+  /// The underlying process.
+  Process _process;
+
+  Future get onExit => _onExitCompleter.future;
+  final _onExitCompleter = new Completer();
+
+  /// A future that completes when the browser process has started.
+  ///
+  /// This is used to ensure that [close] works regardless of when it's called.
+  Future get _onProcessStarted => _onProcessStartedCompleter.future;
+  final _onProcessStartedCompleter = new Completer();
+
+  /// Starts a new instance of PhantomJS open to the given [url], which may be a
+  /// [Uri] or a [String].
+  ///
+  /// If [executable] is passed, it's used as the PhantomJS executable.
+  /// Otherwise the default executable name for the current OS will be used.
+  PhantomJS(url, {String executable}) {
+    if (executable == null) {
+      executable = Platform.isWindows ? "phantomjs.exe" : "phantomjs";
+    }
+
+    // Don't return a Future here because there's no need for the caller to wait
+    // for the process to actually start. They should just wait for the HTTP
+    // request instead.
+    withTempDir((dir) {
+      var script = p.join(dir, "script.js");
+      new File(script).writeAsStringSync(_script);
+
+      return Process.start(executable, [script, url.toString()])
+          .then((process) {
+        // PhantomJS synchronously emits standard output, which means that if we
+        // don't drain its stdout stream it can deadlock.
+        process.stdout.listen((_) {});
+
+        _process = process;
+        _onProcessStartedCompleter.complete();
+
+        return _process.exitCode;
+      });
+    }).then((exitCode) {
+      if (exitCode != 0) throw "PhantomJS failed with exit code $exitCode.";
+    }).then(_onExitCompleter.complete)
+        .catchError(_onExitCompleter.completeError);
+  }
+
+  Future close() {
+    _onProcessStarted.then((_) => _process.kill());
+
+    // Swallow exceptions. The user should explicitly use [onExit] for these.
+    return onExit.catchError((_) {});
+  }
+}