Task: gather elements used in a unit.

pkg/analyzer/test/src/task/dart_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.src.task.dart_test;
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/ast.dart';
@@ skipping 24 matching lines @@
   runReflectiveTests(BuildCompilationUnitElementTaskTest);
   runReflectiveTests(BuildDirectiveElementsTaskTest);
   runReflectiveTests(BuildEnumMemberElementsTaskTest);
   runReflectiveTests(BuildSourceClosuresTaskTest);
   runReflectiveTests(BuildExportNamespaceTaskTest);
   runReflectiveTests(BuildFunctionTypeAliasesTaskTest);
   runReflectiveTests(BuildLibraryConstructorsTaskTest);
   runReflectiveTests(BuildLibraryElementTaskTest);
   runReflectiveTests(BuildPublicNamespaceTaskTest);
   runReflectiveTests(BuildTypeProviderTaskTest);
+  runReflectiveTests(GatherUsedElementsTaskTest);
   runReflectiveTests(GenerateHintsTaskTest);
   runReflectiveTests(ParseDartTaskTest);
   runReflectiveTests(ResolveUnitTypeNamesTaskTest);
   runReflectiveTests(ResolveLibraryTypeNamesTaskTest);
   runReflectiveTests(ResolveReferencesTaskTest);
   runReflectiveTests(ResolveVariableReferencesTaskTest);
   runReflectiveTests(ScanDartTaskTest);
   runReflectiveTests(VerifyUnitTaskTest);
 }
 
@@ skipping 1060 matching lines @@
     // validate
     TypeProvider typeProvider = outputs[TYPE_PROVIDER];
     expect(typeProvider, isNotNull);
     expect(typeProvider.boolType, isNotNull);
     expect(typeProvider.intType, isNotNull);
     expect(typeProvider.futureType, isNotNull);
   }
 }
 
 @reflectiveTest
+class GatherUsedElementsTaskTest extends _AbstractDartTaskTest {
+  UsedElements usedElements;
+  Set<String> usedElementNames;
+
+  test_perform_localVariable() {
+    Source source = _newSource('/test.dart', r'''
+main() {
+  var v1 = 1;
+  var v2 = 2;
+  print(v2);
+}''');
+    _computeUsedElements(source);
+    // validate
+    expect(usedElementNames, unorderedEquals(['v2']));
+  }
+
+  test_perform_method() {
+    Source source = _newSource('/test.dart', r'''
+class A {
+  _m1() {}
+  _m2() {}
+}
+
+main(A a, p) {
+  a._m2();
+  p._m3();
+}
+''');
+    _computeUsedElements(source);
+    // validate
+    print(usedElementNames);
+    print(usedElements.members);
+    expect(usedElementNames, unorderedEquals(['A', 'a', 'p', '_m2']));
+    expect(usedElements.members, unorderedEquals(['_m2', '_m3']));
+  }
+
+  void _computeUsedElements(Source source) {
+    LibraryUnitTarget target = new LibraryUnitTarget(source, source);
+    _computeResult(target, USED_ELEMENTS);
+    expect(task, new isInstanceOf<GatherUsedElementsTask>());
+    usedElements = outputs[USED_ELEMENTS];
+    usedElementNames = usedElements.elements.map((e) => e.name).toSet();
+  }
+}
+
+@reflectiveTest
 class GenerateHintsTaskTest extends _AbstractDartTaskTest {
   test_perform_bestPractices_missingReturn() {
     Source source = _newSource('/test.dart', '''
 int main() {
 }
 ''');
     LibraryUnitTarget target = new LibraryUnitTarget(source, source);
     _computeResult(target, HINTS);
     expect(task, new isInstanceOf<GenerateHintsTask>());
     // validate
@@ skipping 523 matching lines @@
     taskManager.addTaskDescriptor(BuildCompilationUnitElementTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(BuildLibraryConstructorsTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(BuildLibraryElementTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(BuildPublicNamespaceTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(BuildDirectiveElementsTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(BuildSourceClosuresTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(BuildExportNamespaceTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(BuildEnumMemberElementsTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(BuildFunctionTypeAliasesTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(BuildTypeProviderTask.DESCRIPTOR);
+    taskManager.addTaskDescriptor(GatherUsedElementsTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(GenerateHintsTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(ResolveUnitTypeNamesTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(ResolveLibraryTypeNamesTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(ResolveReferencesTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(ResolveVariableReferencesTask.DESCRIPTOR);
     taskManager.addTaskDescriptor(VerifyUnitTask.DESCRIPTOR);
     // prepare AnalysisDriver
     analysisDriver = new AnalysisDriver(taskManager, context);
   }
 
@@ skipping 45 matching lines @@
     return entryMap.putIfAbsent(target, () => new CacheEntry());
   }
 
   TimestampedData<String> getContents(Source source) => source.contents;
 
   noSuchMethod(Invocation invocation) {
     print('noSuchMethod: ${invocation.memberName}');
     return super.noSuchMethod(invocation);
   }
 }