Added back helper file accidentally deleted during test block 219 migration.

tests/lib/mirrors/constructors_test.dart

-// Copyright (c) 2013, 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.constructors_test;
-
-@MirrorsUsed(targets: "test.constructors_test")
-import 'dart:mirrors';
-
-import 'package:expect/expect.dart';
-
-import 'stringify.dart';
-
-constructorsOf(ClassMirror cm) {
-  var result = new Map();
-  cm.declarations.forEach((k, v) {
-    if (v is MethodMirror && v.isConstructor) result[k] = v;
-  });
-  return result;
-}
-
-class Foo {}
-
-class Bar {
-  Bar();
-}
-
-class Baz {
-  Baz.named();
-}
-
-class Biz {
-  Biz();
-  Biz.named();
-}
-
-main() {
-  ClassMirror fooMirror = reflectClass(Foo);
-  Map<Symbol, MethodMirror> fooConstructors = constructorsOf(fooMirror);
-  ClassMirror barMirror = reflectClass(Bar);
-  Map<Symbol, MethodMirror> barConstructors = constructorsOf(barMirror);
-  ClassMirror bazMirror = reflectClass(Baz);
-  Map<Symbol, MethodMirror> bazConstructors = constructorsOf(bazMirror);
-  ClassMirror bizMirror = reflectClass(Biz);
-  Map<Symbol, MethodMirror> bizConstructors = constructorsOf(bizMirror);
-
-  expect('{Foo: Method(s(Foo) in s(Foo), constructor)}', fooConstructors);
-  expect('{Bar: Method(s(Bar) in s(Bar), constructor)}', barConstructors);
-  expect('{Baz.named: Method(s(Baz.named) in s(Baz), constructor)}',
-      bazConstructors);
-  expect(
-      '{Biz: Method(s(Biz) in s(Biz), constructor),'
-      ' Biz.named: Method(s(Biz.named) in s(Biz), constructor)}',
-      bizConstructors);
-  print(bizConstructors);
-
-  expect('[]', fooConstructors.values.single.parameters);
-  expect('[]', barConstructors.values.single.parameters);
-  expect('[]', bazConstructors.values.single.parameters);
-  for (var constructor in bizConstructors.values) {
-    expect('[]', constructor.parameters);
-  }
-
-  expect(
-      '[s()]', fooConstructors.values.map((m) => m.constructorName).toList());
-  expect(
-      '[s()]', barConstructors.values.map((m) => m.constructorName).toList());
-  expect('[s(named)]',
-      bazConstructors.values.map((m) => m.constructorName).toList());
-  expect(
-      '[s(), s(named)]',
-      bizConstructors.values.map((m) => m.constructorName).toList()
-        ..sort(compareSymbols));
-}