tests/compiler/dart2js/unused_empty_map_test.dart

// Copyright (c) 2014, 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.

// Ensure that unused empty HashMap nodes are dropped from the output.

import 'package:expect/expect.dart';
import 'package:async_helper/async_helper.dart';
import 'memory_compiler.dart';

const TEST_SOURCE = const {"main.dart": r"""
void main() {
  var x = {};
  return;
}
"""};

const HASHMAP_EMPTY_CONSTRUCTOR = r"LinkedHashMap_LinkedHashMap$_empty";

main() {
  var collector = new OutputCollector();
  var compiler = compilerFor(TEST_SOURCE, outputProvider: collector);
  asyncTest(() =>
    compiler.run(Uri.parse('memory:main.dart')).then((_) {
      String generated = collector.getOutput('', 'js');
      Expect.isFalse(generated.contains(HASHMAP_EMPTY_CONSTRUCTOR));
    })
  );
}