Send notificatinos after no-op changes.

pkg/analysis_server/test/analysis/update_content_test.dart

 // Copyright (c) 2015, 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 test.analysis.updateContent;
 
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/protocol.dart';
 import 'package:unittest/unittest.dart';
 
@@ skipping 69 matching lines @@
 ''')
       });
       return waitForTasksFinished();
     }).then((_) {
       // The overlay should have been propagated to both contexts, causing both
       // foo.dart and bar.dart to be reanalyzed and found to be free of errors.
       expect(filesErrors[fooPath], isEmpty);
       expect(filesErrors[barPath], isEmpty);
     });
   }
+
+  test_sendNoticesAfterNopChange() async {
+    createProject();
+    addTestFile('');
+    await server.onAnalysisComplete;
+    // add an overlay
+    server.updateContent('1', {
+      testFile: new AddContentOverlay('main() {} main() {}')
+    });
+    await server.onAnalysisComplete;
+    // clear errors and make a no-op change
+    filesErrors.clear();
+    server.updateContent('2', {
+      testFile: new ChangeContentOverlay([new SourceEdit(0, 4, 'main')])
+    });
+    await server.onAnalysisComplete;
+    // errors should have been resent
+    expect(filesErrors, isNotEmpty);
+  }
+
+  test_sendNoticesAfterNopChange_flushedUnit() async {
+    createProject();
+    addTestFile('');
+    await server.onAnalysisComplete;
+    // add an overlay
+    server.updateContent('1', {
+      testFile: new AddContentOverlay('main() {} main() {}')
+    });
+    await server.onAnalysisComplete;
+    // clear errors and make a no-op change
+    filesErrors.clear();
+    server.test_flushResolvedUnit(testFile);
+    server.updateContent('2', {
+      testFile: new ChangeContentOverlay([new SourceEdit(0, 4, 'main')])
+    });
+    await server.onAnalysisComplete;
+    // errors should have been resent
+    expect(filesErrors, isNotEmpty);
+  }
 }