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

pkg/analysis_server/test/analysis/notification_analyzedFiles_test.dart

Index: pkg/analysis_server/test/analysis/notification_analyzedFiles_test.dart
diff --git a/pkg/analysis_server/test/analysis/notification_analyzedFiles_test.dart b/pkg/analysis_server/test/analysis/notification_analyzedFiles_test.dart
index 2cf1606591205aae39239a92b289aa03482e2244..c4fbf14ef28c751f25f28e986b56a1a7b225eff3 100644
--- a/pkg/analysis_server/test/analysis/notification_analyzedFiles_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_analyzedFiles_test.dart
@@ -12,6 +12,7 @@ import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'package:unittest/unittest.dart';
 
 import '../analysis_abstract.dart';
+import '../mocks.dart';
 
 main() {
   groupSep = ' | ';
@@ -21,8 +22,10 @@ main() {
 @reflectiveTest
 class AnalysisNotificationAnalyzedFilesTest extends AbstractAnalysisTest {
   List<String> analyzedFiles;
+  bool analyzedFilesReceived = false;
 
   void assertHasFile(String filePath) {
+    expect(analyzedFilesReceived, isTrue);
     expect(analyzedFiles, contains(filePath));
   }
 
@@ -35,6 +38,7 @@ class AnalysisNotificationAnalyzedFilesTest extends AbstractAnalysisTest {
     if (notification.event == ANALYSIS_ANALYZED_FILES) {
       AnalysisAnalyzedFilesParams params =
           new AnalysisAnalyzedFilesParams.fromNotification(notification);
+      analyzedFilesReceived = true;
       analyzedFiles = params.directories;
     }
   }
@@ -55,7 +59,7 @@ class A {}
     });
   }
 
-  test_definedInInterface_ofInterface() {
+  test_beforeAnalysis() {
     addTestFile('''
 class A {}
 ''');
@@ -63,4 +67,52 @@ class A {}
       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);
+  }
 }