pkg/unittest: Moved `fail` to matcher library

pkg/unittest/test/unittest_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.
 
 // TODO(gram):
 // Unfortunately I can't seem to test anything that involves timeouts, e.g.
 // insufficient callbacks, because the timeout is controlled externally
 // (test.dart?), and we would need to use a shorter timeout for the inner tests
 // so the outer timeout doesn't fire. So I removed all such tests.
 // I'd like to revisit this at some point.
@@ skipping 114 matching lines @@
       });
     } else if (testName == 'async exception test') {
       test(testName, () {
         expectAsync0(() {});
         _defer(() => guardAsync(() { throw "error!"; }));
       });
     } else if (testName == 'late exception test') {
       test('testOne', () {
         var f = expectAsync0(() {});
         _defer(protectAsync0(() {
-          _defer(protectAsync0(() => expect(false, isTrue)));
-          expect(false, isTrue);
+          _defer(protectAsync0(() => fail('first failure')));
+          fail('second failure');
         }));
       });
       test('testTwo', () {
         _defer(expectAsync0(() {}));
       });
     } else if (testName == 'middle exception test') {
       test('testOne', () { expect(true, isTrue); });
       test('testTwo', () { expect(true, isFalse); });
       test('testThree', () {
         var done = expectAsync0((){});
@@ skipping 108 matching lines @@
         var callback = expectAsync0((){});
         var excesscallback = expectAsync0((){});
         return _defer(() {
           excesscallback();
           excesscallback();
           callback();
         });
       });
       test("fail2", () {
         return _defer(() {
-          expect(false, true);
+          fail('failure');
         });
       });
       test('foo5', () {
       });
     } else if (testName == 'test returning future using Timer') {
       test("successful", () {
         return _defer(() {
           Timer.run(() {
             guardAsync(() {
               expect(true, true);
@@ skipping 24 matching lines @@
               callback();
             });
           });
         });
       });
       test("fail2", () {
         var callback = expectAsync0((){});
         return _defer(() {
           Timer.run(() {
             guardAsync(() {
-              expect(false, true);
+              fail('failure');
               callback();
             });
           });
         });
       });
       test('error2', () {
         var callback = expectAsync0((){});
         var excesscallback = expectAsync0((){});
         return _defer(() {
           Timer.run(() {
@@ skipping 73 matching lines @@
         'bad setup/good teardown foo3:bad setup/good teardown '
         'foo3: Test setup failed: Failed to complete setUp:'
         'bad setup/bad teardown foo4:bad setup/bad teardown '
         'foo4: Test teardown failed: Failed to complete tearDown:'
         'post groups'),
     buildStatusString(2, 2, 2,
         'successful::'
         'error1:Callback called more times than expected (3 > 1).:'
         'fail1:Expected: <false> but: was <true>.:'
         'error2:Callback called more times than expected (2 > 1).:'
-        'fail2:Expected: <true> but: was <false>.:'
+        'fail2:failure:'
         'foo5'),
     buildStatusString(2, 2, 2,
         'successful::'
         'fail1:Expected: <false> but: was <true>.:'
         'error1:Callback called more times than expected (3 > 1).:'
-        'fail2:Expected: <true> but: was <false>.:'
+        'fail2:failure:'
         'error2:Callback called more times than expected (2 > 1).:'
         'foo6'),
   ];
 
   actual = [];
 
   nextTest(0);
 }