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

pkg/matcher/test/throws_matchers_test.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.core_matchers_test;
-
-import 'package:matcher/matcher.dart';
-import 'package:unittest/unittest.dart' show test, group;
-
-import 'test_utils.dart';
-
-void main() {
-  initUtils();
-
-
-  test('throws', () {
-    shouldFail(doesNotThrow, throws,
-        matches(
-            r"Expected: throws"
-            r"  Actual: <Closure(: \(\) => dynamic "
-            r"from Function 'doesNotThrow': static\.)?>"
-            r"   Which: did not throw"));
-    shouldPass(doesThrow, throws);
-    shouldFail(true, throws,
-        "Expected: throws"
-        "  Actual: <true>"
-        "   Which: is not a Function or Future");
-  });
-
-  test('throwsA', () {
-    shouldPass(doesThrow, throwsA(equals('X')));
-    shouldFail(doesThrow, throwsA(equals('Y')),
-        matches(
-            r"Expected: throws 'Y'"
-            r"  Actual: <Closure(: \(\) => dynamic "
-            r"from Function 'doesThrow': static\.)?>"
-            r"   Which: threw 'X'"));
-  });
-
-  test('throwsA', () {
-    shouldPass(doesThrow, throwsA(equals('X')));
-    shouldFail(doesThrow, throwsA(equals('Y')),
-        matches("Expected: throws 'Y'.*"
-        "Actual: <Closure.*"
-        "Which: threw 'X'"));
-  });
-
-
-  group('exception/error matchers', () {
-    test('throwsCyclicInitializationError', () {
-      expect(() => _Bicycle.foo, throwsCyclicInitializationError);
-    });
-
-    test('throwsConcurrentModificationError', () {
-      expect(() {
-        var a = { 'foo': 'bar' };
-        for (var k in a.keys) {
-          a.remove(k);
-        }
-      }, throwsConcurrentModificationError);
-    });
-
-    test('throwsNullThrownError', () {
-      expect(() => throw null, throwsNullThrownError);
-    });
-  });
-}
-
-class _Bicycle {
-  static final foo = bar();
-
-  static bar() {
-    return foo + 1;
-  }
-}
-