Issue 20827. Import required type in 'Extract Method' refactoring.

pkg/analysis_server/test/services/refactoring/extract_method_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.services.refactoring.extract_method;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/correction/status.dart';
@@ skipping 1355 matching lines @@
     return _assertSuccessfulRefactoring('''
 typedef R Foo<S, R>(S s);
 void main(Foo<String, int> foo, String s) {
   int a = res(foo, s);
 }
 
 int res(Foo<String, int> foo, String s) => foo(s);
 ''');
   }
 
+  test_singleExpression_returnType_importLibrary() async {
+    _addLibraryReturningAsync();
+    indexTestUnit('''
+import 'asyncLib.dart';
+main() {
+  var a = newFuture();
+}
+''');
+    _createRefactoringForString('newFuture()');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+import 'asyncLib.dart';
+import 'dart:async';
+main() {
+  var a = res();
+}
+
+Future<int> res() => newFuture();
+''');
+  }
+
   test_singleExpression_returnTypeGeneric() {
     indexTestUnit('''
 main() {
   var v = new List<String>();
 }
 ''');
     _createRefactoringForString('new List<String>()');
     // apply refactoring
     return _assertSuccessfulRefactoring('''
 main() {
@@ skipping 810 matching lines @@
   res(a);
 // end
 }
 
 void res(int a) {
   print(a);
 }
 ''');
   }
 
+  test_statements_parameters_importType() {
+    _addLibraryReturningAsync();
+    indexTestUnit('''
+import 'asyncLib.dart';
+main() {
+  var v = newFuture();
+// start
+  print(v);
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+import 'asyncLib.dart';
+import 'dart:async';
+main() {
+  var v = newFuture();
+// start
+  res(v);
+// end
+}
+
+void res(Future<int> v) {
+  print(v);
+}
+''');
+  }
+
   test_statements_return_last() {
     indexTestUnit('''
 main() {
 // start
   int v = 5;
   return v + 1;
 // end
 }
 ''');
     _createRefactoringForStartEndComments();
@@ skipping 183 matching lines @@
   print(0);
 }
 
 void res() {
   print(0);
   print(0);
 }
 ''');
   }
 
+  void _addLibraryReturningAsync() {
+    addSource('/asyncLib.dart', r'''
+library asyncLib;
+import 'dart:async';
+Future<int> newFuture() => null;
+''');
+  }
+
   Future _assertConditionsError(String message) async {
     RefactoringStatus status = await refactoring.checkAllConditions();
     assertRefactoringStatus(
         status,
         RefactoringProblemSeverity.ERROR,
         expectedMessage: message);
   }
 
   Future _assertConditionsFatal(String message) async {
     RefactoringStatus status = await refactoring.checkAllConditions();
@@ skipping 66 matching lines @@
    * Returns a deep copy of [refactoring] parameters.
    * There was a bug masked by updating parameter instances shared between the
    * refactoring and the test.
    */
   List<RefactoringMethodParameter> _getParametersCopy() {
     return refactoring.parameters.map((p) {
       return new RefactoringMethodParameter(p.kind, p.type, p.name, id: p.id);
     }).toList();
   }
 }