pkg/unittest: readonly view of testCase collection

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 276 matching lines @@
               excesscallback();
               excesscallback();
               excesscallback();
               callback();
             });
           });
         });
       });
       test('foo6', () {
       });
+    } else if (testName == 'testCases immutable') {
+      test(testName, () {
+        expect(() => testCases.clear(), throwsUnsupportedError);
+        expect(() => testCases.removeLast(), throwsUnsupportedError);
+      });
     }
   });
 }
 
 void nextTest(int testNum) {
   SendPort sport = spawnFunction(runTest);
   sport.call(tests[testNum]).then((msg) {
     actual.add(msg);
     if (actual.length == expected.length) {
       for (var i = 0; i < tests.length; i++) {
@@ skipping 15 matching lines @@
     'teardown test',
     'setup and teardown test',
     'correct callback test',
     'excess callback test',
     'completion test',
     'async exception test',
     'late exception test',
     'middle exception test',
     'async setup/teardown test',
     'test returning future',
-    'test returning future using Timer'
+    'test returning future using Timer',
+    'testCases immutable'
   ];
 
   expected = [
     buildStatusString(1, 0, 0, tests[0]),
     buildStatusString(0, 1, 0, tests[1],
         message: 'Expected: <5> but: was <4>.'),
     buildStatusString(0, 1, 0, tests[2], message: 'Caught Exception: Fail.'),
     buildStatusString(2, 0, 0, 'a a::a b b'),
     buildStatusString(1, 0, 0, 'a ${tests[4]}', count: 0, setup: 'setup'),
     buildStatusString(1, 0, 0, 'a ${tests[5]}', count: 0, setup: '',
@@ skipping 26 matching lines @@
         'error2:Callback called more times than expected (1).:'
         'fail2:failure:'
         'foo5'),
     buildStatusString(2, 4, 0,
         'successful::'
         'fail1:Expected: <false> but: was <true>.:'
         'error1:Callback called more times than expected (1).:'
         'fail2:failure:'
         'error2:Callback called more times than expected (1).:'
         'foo6'),
+    buildStatusString(1, 0, 0, 'testCases immutable'),
   ];
 
   actual = [];
 
   nextTest(0);
 }