Only send "analysis.analyzedFiles" notification when the set of files changes.

pkg/analysis_server/test/analysis/notification_analyzedFiles_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.analysis.notification.analyzedDirectories;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/protocol.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'package:unittest/unittest.dart';
 
 import '../analysis_abstract.dart';
+import '../mocks.dart';
 
 main() {
   groupSep = ' | ';
   defineReflectiveTests(AnalysisNotificationAnalyzedFilesTest);
 }
 
 @reflectiveTest
 class AnalysisNotificationAnalyzedFilesTest extends AbstractAnalysisTest {
   List<String> analyzedFiles;
+  bool analyzedFilesReceived = false;
 
   void assertHasFile(String filePath) {
+    expect(analyzedFilesReceived, isTrue);
     expect(analyzedFiles, contains(filePath));
   }
 
   Future prepareAnalyzedFiles() {
     addGeneralAnalysisSubscription(GeneralAnalysisService.ANALYZED_FILES);
     return waitForTasksFinished();
   }
 
   void processNotification(Notification notification) {
     if (notification.event == ANALYSIS_ANALYZED_FILES) {
       AnalysisAnalyzedFilesParams params =
           new AnalysisAnalyzedFilesParams.fromNotification(notification);
+      analyzedFilesReceived = true;
       analyzedFiles = params.directories;
     }
   }
 
   void setUp() {
     super.setUp();
     createProject();
   }
 
   test_afterAnalysis() {
     addTestFile('''
 class A {}
 ''');
     return waitForTasksFinished().then((_) {
       return prepareAnalyzedFiles().then((_) {
         assertHasFile(testFile);
       });
     });
   }
 
-  test_definedInInterface_ofInterface() {
+  test_beforeAnalysis() {
     addTestFile('''
 class A {}
 ''');
     return prepareAnalyzedFiles().then((_) {
       assertHasFile(testFile);
     });
   }
+
+  test_insignificant_change() async {
+    // Making a change that doesn't affect the set of reachable files should
+    // not trigger the notification to be re-sent.
+    addTestFile('class A {}');
+    await prepareAnalyzedFiles();
+    await waitForTasksFinished();
+    expect(analyzedFilesReceived, isTrue);
+    analyzedFilesReceived = false;
+    modifyTestFile('class B {}');
+    await pumpEventQueue();
+    await waitForTasksFinished();
+    expect(analyzedFilesReceived, isFalse);
+  }
+
+  test_resubscribe_no_changes() async {
+    // Unsubscribing and resubscribing should cause the notification to be
+    // re-sent, even if nothing has changed.
+    addTestFile('class A {}');
+    await prepareAnalyzedFiles();
+    await waitForTasksFinished();
+    expect(analyzedFilesReceived, isTrue);
+    unsubscribeAnalyzedFiles();
+    analyzedFilesReceived = false;
+    await prepareAnalyzedFiles();
+    expect(analyzedFilesReceived, isTrue);
+    assertHasFile(testFile);
+  }
+
+  test_significant_change() async {
+    // Making a change that *does* affect the set of reachable files should
+    // trigger the notification to be re-sent.
+    addTestFile('class A {}');
+    addFile('/foo.dart', 'library foo');
+    await prepareAnalyzedFiles();
+    await waitForTasksFinished();
+    expect(analyzedFilesReceived, isTrue);
+    analyzedFilesReceived = false;
+    modifyTestFile('import "/foo.dart";');
+    await pumpEventQueue();
+    await waitForTasksFinished();
+    expect(analyzedFilesReceived, isTrue);
+    assertHasFile('/foo.dart');
+  }
+
+  void unsubscribeAnalyzedFiles() {
+    removeGeneralAnalysisSubscription(GeneralAnalysisService.ANALYZED_FILES);
+  }
 }