Split unittest tests into separate test files.

pkg/unittest/test/unittest_nested_groups_setup_teardown_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 unittestTest;
+import 'dart:isolate';
+import 'dart:async';
+import 'package:unittest/unittest.dart';
+
+part 'unittest_test_utils.dart';
+
+var testName = 'nested groups setup/teardown';
+
+var testFunction = (_) {
+  StringBuffer s = new StringBuffer();
+  group('level 1', () {
+    setUp(makeDelayedSetup(1, s));
+    group('level 2', () {
+      setUp(makeImmediateSetup(2, s));
+      tearDown(makeDelayedTeardown(2, s));
+      group('level 3', () {
+        group('level 4', () {
+          setUp(makeDelayedSetup(4, s));
+          tearDown(makeImmediateTeardown(4, s));
+          group('level 5', () {
+            setUp(makeImmediateSetup(5, s));
+            group('level 6', () {
+              tearDown(makeDelayedTeardown(6, s));
+              test('inner', () {});
+            });
+          });
+        });
+      });
+    });
+  });
+  test('after nest', () {
+    expect(s.toString(), "l1 U l2 U l4 U l5 U l6 D l4 D l2 D ");
+  });
+};
+
+var expected = buildStatusString(2, 0, 0,
+    'level 1 level 2 level 3 level 4 level 5 level 6 inner::'
+    'after nest');