Re-apply "Remove unittest and matcher from the repo."

pkg/matcher/test/test_utils.dart

-// Copyright (c) 2012, 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 matcher.test_utils;
-
-import 'dart:async';
-
-import 'package:matcher/matcher.dart';
-import 'package:unittest/unittest.dart' show test, expectAsync;
-
-int _errorCount;
-String _errorString;
-FailureHandler _testHandler = null;
-
-class MyFailureHandler extends DefaultFailureHandler {
-  void fail(String reason) {
-    ++_errorCount;
-    _errorString = reason;
-  }
-}
-
-void initUtils() {
-  if (_testHandler == null) {
-    _testHandler = new MyFailureHandler();
-  }
-}
-
-void shouldFail(value, Matcher matcher, expected, {bool isAsync: false}) {
-  configureExpectFailureHandler(_testHandler);
-  _errorCount = 0;
-  _errorString = '';
-  expect(value, matcher);
-  afterTest() {
-    configureExpectFailureHandler(null);
-    expect(_errorCount, equals(1));
-    if (expected is String) {
-      expect(_errorString, equalsIgnoringWhitespace(expected));
-    } else {
-      expect(_errorString.replaceAll('\n', ''), expected);
-    }
-  }
-
-  if (isAsync) {
-    Timer.run(expectAsync(afterTest));
-  } else {
-    afterTest();
-  }
-}
-
-void shouldPass(value, Matcher matcher, {bool isAsync: false}) {
-  configureExpectFailureHandler(_testHandler);
-  _errorCount = 0;
-  _errorString = '';
-  expect(value, matcher);
-  afterTest() {
-    configureExpectFailureHandler(null);
-    expect(_errorCount, equals(0));
-  }
-  if (isAsync) {
-    Timer.run(expectAsync(afterTest));
-  } else {
-    afterTest();
-  }
-}
-
-doesNotThrow() {}
-doesThrow() { throw 'X'; }
-
-class PrefixMatcher extends Matcher {
-  final String _prefix;
-  const PrefixMatcher(this._prefix);
-  bool matches(item, Map matchState) {
-    return item is String &&
-        (collapseWhitespace(item)).startsWith(collapseWhitespace(_prefix));
-  }
-
-  Description describe(Description description) =>
-    description.add('a string starting with ').
-        addDescriptionOf(collapseWhitespace(_prefix)).
-        add(' ignoring whitespace');
-}