Trigger re-analysis when a file changes on disk.

pkg/analysis_server/test/domain_analysis_test.dart

 // Copyright (c) 2014, 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.domain.analysis;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/computer/computer_highlights.dart';
 import 'package:analysis_server/src/analysis_server.dart';
@@ skipping 1568 matching lines @@
         NEW_LENGTH: 'lib'.length,
       });
       // wait, there is an error
       return helper.waitForOperationsFinished().then((_) {
         List<AnalysisError> errors = helper.getTestErrors();
         expect(errors, hasLength(1));
       });
     });
   });
 
-  test('change on disk', () {
+  test('change on disk, normal', () {
     AnalysisTestHelper helper = new AnalysisTestHelper();
     helper.createSingleFileProject('library A;');
     return helper.waitForOperationsFinished().then((_) {
+      // There should be no errors
+      expect(helper.getTestErrors(), hasLength(0));
+      // Change file on disk, adding a syntax error.
+      helper.resourceProvider.modifyFile(helper.testFile, 'library lib');
+      // There should be errors now.
+      return pumpEventQueue().then((_) {
+        return helper.waitForOperationsFinished().then((_) {
+          expect(helper.getTestErrors(), hasLength(1));
+        });
+      });
+    });
+  });
+
+  test('change on disk, during override', () {
+    AnalysisTestHelper helper = new AnalysisTestHelper();
+    helper.createSingleFileProject('library A;');
+    return helper.waitForOperationsFinished().then((_) {
       // update code
       helper.sendContentChange({
         CONTENT: 'library B;'
       });
       // There should be no errors
       return helper.waitForOperationsFinished().then((_) {
         expect(helper.getTestErrors(), hasLength(0));
         // Change file on disk, adding a syntax error.
         helper.resourceProvider.modifyFile(helper.testFile, 'library lib');
         // There should still be no errors (file should not have been reread).
@@ skipping 39 matching lines @@
       // subscribe
       helper.addAnalysisSubscriptionHighlights(helper.testFile);
       // wait, has regions
       return helper.waitForOperationsFinished().then((_) {
         var highlights = helper.getHighlights(helper.testFile);
         expect(highlights, isNot(isEmpty));
       });
     });
   });
 }