Add SearchEngine.membersOfSubtypes().

pkg/analysis_server/test/services/search/search_engine_test.dart

Index: pkg/analysis_server/test/services/search/search_engine_test.dart
diff --git a/pkg/analysis_server/test/services/search/search_engine_test.dart b/pkg/analysis_server/test/services/search/search_engine_test.dart
index 228a9069d8c32e34446169062bd047807e81382c..04ef87313b65e312ada041bc66c36dd2b33d4ee9 100644
--- a/pkg/analysis_server/test/services/search/search_engine_test.dart
+++ b/pkg/analysis_server/test/services/search/search_engine_test.dart
@@ -46,6 +46,123 @@ class SearchEngineImpl2Test {
     scheduler.start();
   }
 
+  test_membersOfSubtypes_hasMembers() async {
+    var a = _p('/test/a.dart');
+    var b = _p('/test/b.dart');
+    var c = _p('/test/c.dart');
+
+    provider.newFile(
+        a,
+        '''
+class A {
+  void a() {}
+  void b() {}
+  void c() {}
+}
+''');
+    provider.newFile(
+        b,
+        '''
+import 'a.dart';
+class B extends A {
+  void a() {}
+}
+''');
+    provider.newFile(
+        c,
+        '''
+import 'a.dart';
+class C extends A {
+  void b() {}
+}
+''');
+
+    var driver1 = _newDriver();
+    var driver2 = _newDriver();
+
+    driver1.addFile(a);
+    driver2.addFile(b);
+    driver2.addFile(c);
+    await scheduler.waitForIdle();
+
+    var resultA = await driver1.getResult(a);
+    ClassElement elementA = resultA.unit.element.types[0];
+
+    var searchEngine = new SearchEngineImpl([driver1, driver2]);
+    Set<String> members = await searchEngine.membersOfSubtypes(elementA);
+    expect(members, unorderedEquals(['a', 'b']));
+  }
+
+  test_membersOfSubtypes_noMembers() async {
+    var a = _p('/test/a.dart');
+    var b = _p('/test/b.dart');
+
+    provider.newFile(
+        a,
+        '''
+class A {
+  void a() {}
+  void b() {}
+  void c() {}
+}
+''');
+    provider.newFile(
+        b,
+        '''
+import 'a.dart';
+class B extends A {}
+''');
+
+    var driver = _newDriver();
+
+    driver.addFile(a);
+    driver.addFile(b);
+    await scheduler.waitForIdle();
+
+    var resultA = await driver.getResult(a);
+    ClassElement elementA = resultA.unit.element.types[0];
+
+    var searchEngine = new SearchEngineImpl([driver]);
+    Set<String> members = await searchEngine.membersOfSubtypes(elementA);
+    expect(members, isEmpty);
+  }
+
+  test_membersOfSubtypes_noSubtypes() async {
+    var a = _p('/test/a.dart');
+    var b = _p('/test/b.dart');
+
+    provider.newFile(
+        a,
+        '''
+class A {
+  void a() {}
+  void b() {}
+  void c() {}
+}
+''');
+    provider.newFile(
+        b,
+        '''
+import 'a.dart';
+class B {
+  void a() {}
+}
+''');
+
+    var driver = _newDriver();
+
+    driver.addFile(a);
+    driver.addFile(b);
+    await scheduler.waitForIdle();
+
+    var resultA = await driver.getResult(a);
+    ClassElement elementA = resultA.unit.element.types[0];
+
+    var searchEngine = new SearchEngineImpl([driver]);
+    Set<String> members = await searchEngine.membersOfSubtypes(elementA);
+    expect(members, isNull);
+  }
+
   test_searchAllSubtypes() async {
     var p = _p('/test.dart');