Make FixContributor asynchronous.

pkg/analysis_server/test/services/correction/fix_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.correction.fix;
 
+import 'dart:async';
+
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
+import 'package:analysis_server/plugin/edit/fix/fix_dart.dart';
 import 'package:analysis_server/plugin/protocol/protocol.dart'
     hide AnalysisError;
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/fix_internal.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/source/package_map_resolver.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
@@ skipping 17 matching lines @@
         error.errorCode != HintCode.UNUSED_CATCH_STACK &&
         error.errorCode != HintCode.UNUSED_ELEMENT &&
         error.errorCode != HintCode.UNUSED_FIELD &&
         error.errorCode != HintCode.UNUSED_LOCAL_VARIABLE;
   };
 
   Fix fix;
   SourceChange change;
   String resultCode;
 
-  void assert_undefinedFunction_create_returnType_bool(String lineWithTest) {
+  assert_undefinedFunction_create_returnType_bool(String lineWithTest) async {
     resolveTestUnit('''
 main() {
   bool b = true;
   $lineWithTest
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   bool b = true;
   $lineWithTest
 }
 
 bool test() {
 }
 ''');
   }
 
-  void assertHasFix(FixKind kind, String expected) {
+  assertHasFix(FixKind kind, String expected) async {
     AnalysisError error = _findErrorToFix();
-    fix = _assertHasFix(kind, error);
+    fix = await _assertHasFix(kind, error);
     change = fix.change;
     // apply to "file"
     List<SourceFileEdit> fileEdits = change.edits;
     expect(fileEdits, hasLength(1));
     resultCode = SourceEdit.applySequence(testCode, change.edits[0].edits);
     // verify
     expect(resultCode, expected);
   }
 
-  void assertNoFix(FixKind kind) {
+  assertNoFix(FixKind kind) async {
     AnalysisError error = _findErrorToFix();
-    List<Fix> fixes = _computeFixes(error);
+    List<Fix> fixes = await _computeFixes(error);
     for (Fix fix in fixes) {
       if (fix.kind == kind) {
         throw fail('Unexpected fix $kind in\n${fixes.join('\n')}');
       }
     }
   }
 
   Position expectedPosition(String search) {
     int offset = resultCode.indexOf(search);
     return new Position(testFile, offset);
@@ skipping 12 matching lines @@
     return values.map((value) {
       return new LinkedEditSuggestion(value, kind);
     }).toList();
   }
 
   void setUp() {
     super.setUp();
     verifyNoTestUnitErrors = false;
   }
 
-  void test_addFieldFormalParameters_hasRequiredParameter() {
+  test_addFieldFormalParameters_hasRequiredParameter() async {
     resolveTestUnit('''
 class Test {
   final int a;
   final int b;
   final int c;
   Test(this.a);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_FIELD_FORMAL_PARAMETERS,
         '''
 class Test {
   final int a;
   final int b;
   final int c;
   Test(this.a, this.b, this.c);
 }
 ''');
   }
 
-  void test_addFieldFormalParameters_noParameters() {
+  test_addFieldFormalParameters_noParameters() async {
     resolveTestUnit('''
 class Test {
   final int a;
   final int b;
   final int c;
   Test();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_FIELD_FORMAL_PARAMETERS,
         '''
 class Test {
   final int a;
   final int b;
   final int c;
   Test(this.a, this.b, this.c);
 }
 ''');
   }
 
-  void test_addFieldFormalParameters_noRequiredParameter() {
+  test_addFieldFormalParameters_noRequiredParameter() async {
     resolveTestUnit('''
 class Test {
   final int a;
   final int b;
   final int c;
   Test([this.c]);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_FIELD_FORMAL_PARAMETERS,
         '''
 class Test {
   final int a;
   final int b;
   final int c;
   Test(this.a, this.b, [this.c]);
 }
 ''');
   }
 
-  void test_addMissingParameter_function_positional_hasZero() {
+  test_addMissingParameter_function_positional_hasZero() async {
     resolveTestUnit('''
 test() {}
 main() {
   test(1);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_MISSING_PARAMETER_POSITIONAL,
         '''
 test([int i]) {}
 main() {
   test(1);
 }
 ''');
   }
 
-  void test_addMissingParameter_function_required_hasOne() {
+  test_addMissingParameter_function_required_hasOne() async {
     resolveTestUnit('''
 test(int a) {}
 main() {
   test(1, 2.0);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_MISSING_PARAMETER_REQUIRED,
         '''
 test(int a, double d) {}
 main() {
   test(1, 2.0);
 }
 ''');
   }
 
-  void test_addMissingParameter_function_required_hasZero() {
+  test_addMissingParameter_function_required_hasZero() async {
     resolveTestUnit('''
 test() {}
 main() {
   test(1);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_MISSING_PARAMETER_REQUIRED,
         '''
 test(int i) {}
 main() {
   test(1);
 }
 ''');
   }
 
-  void test_addMissingParameter_method_positional_hasOne() {
+  test_addMissingParameter_method_positional_hasOne() async {
     resolveTestUnit('''
 class A {
   test(int a) {}
   main() {
     test(1, 2.0);
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_MISSING_PARAMETER_POSITIONAL,
         '''
 class A {
   test(int a, [double d]) {}
   main() {
     test(1, 2.0);
   }
 }
 ''');
   }
 
-  void test_addMissingParameter_method_required_hasOne() {
+  test_addMissingParameter_method_required_hasOne() async {
     resolveTestUnit('''
 class A {
   test(int a) {}
   main() {
     test(1, 2.0);
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_MISSING_PARAMETER_REQUIRED,
         '''
 class A {
   test(int a, double d) {}
   main() {
     test(1, 2.0);
   }
 }
 ''');
   }
 
-  void test_addMissingParameter_method_required_hasZero() {
+  test_addMissingParameter_method_required_hasZero() async {
     resolveTestUnit('''
 class A {
   test() {}
   main() {
     test(1);
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_MISSING_PARAMETER_REQUIRED,
         '''
 class A {
   test(int i) {}
   main() {
     test(1);
   }
 }
 ''');
   }
 
-  void test_addPartOfDirective() {
+  test_addPartOfDirective() async {
     String partCode = r'''
 // Comment first.
 // Comment second.
 
 class A {}
 ''';
     addSource('/part.dart', partCode);
     resolveTestUnit('''
 library my.lib;
 part 'part.dart';
 ''');
     _performAnalysis();
     AnalysisError error = _findErrorToFix();
-    fix = _assertHasFix(DartFixKind.ADD_PART_OF, error);
+    fix = await _assertHasFix(DartFixKind.ADD_PART_OF, error);
     change = fix.change;
     // apply to "file"
     List<SourceFileEdit> fileEdits = change.edits;
     expect(fileEdits, hasLength(1));
     SourceFileEdit fileEdit = change.edits[0];
     expect(fileEdit.file, '/part.dart');
     expect(
         SourceEdit.applySequence(partCode, fileEdit.edits),
         r'''
 // Comment first.
 // Comment second.
 
 part of my.lib;
 
 class A {}
 ''');
   }
 
-  void test_addSync_BAD_nullFunctionBody() {
+  test_addSync_BAD_nullFunctionBody() async {
     resolveTestUnit('''
 var F = await;
 ''');
-    assertNoFix(DartFixKind.ADD_ASYNC);
+    await assertNoFix(DartFixKind.ADD_ASYNC);
   }
 
-  void test_addSync_blockFunctionBody() {
+  test_addSync_blockFunctionBody() async {
     resolveTestUnit('''
 foo() {}
 main() {
   await foo();
 }
 ''');
     List<AnalysisError> errors = context.computeErrors(testSource);
     expect(errors, hasLength(2));
     String message1 = "Expected to find ';'";
     String message2 = "Undefined name 'await'";
     expect(errors.map((e) => e.message), unorderedEquals([message1, message2]));
     for (AnalysisError error in errors) {
       if (error.message == message1) {
-        List<Fix> fixes = _computeFixes(error);
+        List<Fix> fixes = await _computeFixes(error);
         expect(fixes, isEmpty);
       }
       if (error.message == message2) {
-        List<Fix> fixes = _computeFixes(error);
+        List<Fix> fixes = await _computeFixes(error);
         // has exactly one fix
         expect(fixes, hasLength(1));
         Fix fix = fixes[0];
         expect(fix.kind, DartFixKind.ADD_ASYNC);
         // apply to "file"
         List<SourceFileEdit> fileEdits = fix.change.edits;
         expect(fileEdits, hasLength(1));
         resultCode = SourceEdit.applySequence(testCode, fileEdits[0].edits);
         // verify
         expect(
             resultCode,
             '''
 foo() {}
 main() async {
   await foo();
 }
 ''');
       }
     }
   }
 
-  void test_addSync_expressionFunctionBody() {
+  test_addSync_expressionFunctionBody() async {
     errorFilter = (AnalysisError error) {
       return error.errorCode == StaticWarningCode.UNDEFINED_IDENTIFIER;
     };
     resolveTestUnit('''
 foo() {}
 main() => await foo();
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_ASYNC,
         '''
 foo() {}
 main() async => await foo();
 ''');
   }
 
-  void test_boolean() {
+  test_boolean() async {
     resolveTestUnit('''
 main() {
   boolean v;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REPLACE_BOOLEAN_WITH_BOOL,
         '''
 main() {
   bool v;
 }
 ''');
   }
 
-  void test_canBeNullAfterNullAware_chain() {
+  test_canBeNullAfterNullAware_chain() async {
     resolveTestUnit('''
 main(x) {
   x?.a.b.c;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REPLACE_WITH_NULL_AWARE,
         '''
 main(x) {
   x?.a?.b?.c;
 }
 ''');
   }
 
-  void test_canBeNullAfterNullAware_methodInvocation() {
+  test_canBeNullAfterNullAware_methodInvocation() async {
     resolveTestUnit('''
 main(x) {
   x?.a.b();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REPLACE_WITH_NULL_AWARE,
         '''
 main(x) {
   x?.a?.b();
 }
 ''');
   }
 
-  void test_canBeNullAfterNullAware_propertyAccess() {
+  test_canBeNullAfterNullAware_propertyAccess() async {
     resolveTestUnit('''
 main(x) {
   x?.a().b;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REPLACE_WITH_NULL_AWARE,
         '''
 main(x) {
   x?.a()?.b;
 }
 ''');
   }
 
-  void test_changeToStaticAccess_method() {
+  test_changeToStaticAccess_method() async {
     resolveTestUnit('''
 class A {
   static foo() {}
 }
 main(A a) {
   a.foo();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO_STATIC_ACCESS,
         '''
 class A {
   static foo() {}
 }
 main(A a) {
   A.foo();
 }
 ''');
   }
 
-  void test_changeToStaticAccess_method_importType() {
+  test_changeToStaticAccess_method_importType() async {
     addSource(
         '/libA.dart',
         r'''
 library libA;
 class A {
   static foo() {}
 }
 ''');
     addSource(
         '/libB.dart',
         r'''
 library libB;
 import 'libA.dart';
 class B extends A {}
 ''');
     resolveTestUnit('''
 import 'libB.dart';
 main(B b) {
   b.foo();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO_STATIC_ACCESS,
         '''
 import 'libB.dart';
 import 'libA.dart';
 main(B b) {
   A.foo();
 }
 ''');
   }
 
-  void test_changeToStaticAccess_method_prefixLibrary() {
+  test_changeToStaticAccess_method_prefixLibrary() async {
     resolveTestUnit('''
 import 'dart:async' as pref;
 main(pref.Future f) {
   f.wait([]);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO_STATIC_ACCESS,
         '''
 import 'dart:async' as pref;
 main(pref.Future f) {
   pref.Future.wait([]);
 }
 ''');
   }
 
-  void test_changeToStaticAccess_property() {
+  test_changeToStaticAccess_property() async {
     resolveTestUnit('''
 class A {
   static get foo => 42;
 }
 main(A a) {
   a.foo;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO_STATIC_ACCESS,
         '''
 class A {
   static get foo => 42;
 }
 main(A a) {
   A.foo;
 }
 ''');
   }
 
-  void test_changeToStaticAccess_property_importType() {
+  test_changeToStaticAccess_property_importType() async {
     addSource(
         '/libA.dart',
         r'''
 library libA;
 class A {
   static get foo => null;
 }
 ''');
     addSource(
         '/libB.dart',
         r'''
 library libB;
 import 'libA.dart';
 class B extends A {}
 ''');
     resolveTestUnit('''
 import 'libB.dart';
 main(B b) {
   b.foo;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO_STATIC_ACCESS,
         '''
 import 'libB.dart';
 import 'libA.dart';
 main(B b) {
   A.foo;
 }
 ''');
   }
 
-  void test_createClass() {
+  test_createClass() async {
     resolveTestUnit('''
 main() {
   Test v = null;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_CLASS,
         '''
 main() {
   Test v = null;
 }
 
 class Test {
 }
 ''');
     _assertLinkedGroup(change.linkedEditGroups[0], ['Test v =', 'Test {']);
   }
 
-  void test_createClass_BAD_hasUnresolvedPrefix() {
+  test_createClass_BAD_hasUnresolvedPrefix() async {
     resolveTestUnit('''
 main() {
   prefix.Test v = null;
 }
 ''');
-    assertNoFix(DartFixKind.CREATE_CLASS);
+    await assertNoFix(DartFixKind.CREATE_CLASS);
   }
 
-  void test_createClass_inLibraryOfPrefix() {
+  test_createClass_inLibraryOfPrefix() async {
     String libCode = r'''
 library my.lib;
 
 class A {}
 ''';
     addSource('/lib.dart', libCode);
     resolveTestUnit('''
 import 'lib.dart' as lib;
 
 main() {
   lib.A a = null;
   lib.Test t = null;
 }
 ''');
     AnalysisError error = _findErrorToFix();
-    fix = _assertHasFix(DartFixKind.CREATE_CLASS, error);
+    fix = await _assertHasFix(DartFixKind.CREATE_CLASS, error);
     change = fix.change;
     // apply to "lib.dart"
     List<SourceFileEdit> fileEdits = change.edits;
     expect(fileEdits, hasLength(1));
     SourceFileEdit fileEdit = change.edits[0];
     expect(fileEdit.file, '/lib.dart');
     expect(
         SourceEdit.applySequence(libCode, fileEdit.edits),
         r'''
 library my.lib;
 
 class A {}
 
 class Test {
 }
 ''');
     expect(change.linkedEditGroups, isEmpty);
   }
 
-  void test_createClass_innerLocalFunction() {
+  test_createClass_innerLocalFunction() async {
     resolveTestUnit('''
 f() {
   g() {
     Test v = null;
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_CLASS,
         '''
 f() {
   g() {
     Test v = null;
   }
 }
 
 class Test {
 }
 ''');
     _assertLinkedGroup(change.linkedEditGroups[0], ['Test v =', 'Test {']);
   }
 
-  void test_createClass_itemOfList() {
+  test_createClass_itemOfList() async {
     resolveTestUnit('''
 main() {
   var a = [Test];
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_CLASS,
         '''
 main() {
   var a = [Test];
 }
 
 class Test {
 }
 ''');
     _assertLinkedGroup(change.linkedEditGroups[0], ['Test];', 'Test {']);
   }
 
-  void test_createClass_itemOfList_inAnnotation() {
+  test_createClass_itemOfList_inAnnotation() async {
     errorFilter = (AnalysisError error) {
       return error.errorCode == StaticWarningCode.UNDEFINED_IDENTIFIER;
     };
     resolveTestUnit('''
 class MyAnnotation {
   const MyAnnotation(a, b);
 }
 @MyAnnotation(int, const [Test])
 main() {}
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_CLASS,
         '''
 class MyAnnotation {
   const MyAnnotation(a, b);
 }
 @MyAnnotation(int, const [Test])
 main() {}
 
 class Test {
 }
 ''');
     _assertLinkedGroup(change.linkedEditGroups[0], ['Test])', 'Test {']);
   }
 
-  void test_createConstructor_forFinalFields() {
+  test_createConstructor_forFinalFields() async {
     errorFilter = (AnalysisError error) {
       return error.message.contains("'a'");
     };
     resolveTestUnit('''
 class Test {
   final int a;
   final int b = 2;
   final int c;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_CONSTRUCTOR_FOR_FINAL_FIELDS,
         '''
 class Test {
   final int a;
   final int b = 2;
   final int c;
 
   Test(this.a, this.c);
 }
 ''');
   }
 
-  void test_createConstructor_insteadOfSyntheticDefault() {
+  test_createConstructor_insteadOfSyntheticDefault() async {
     resolveTestUnit('''
 class A {
   int field;
 
   method() {}
 }
 main() {
   new A(1, 2.0);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_CONSTRUCTOR,
         '''
 class A {
   int field;
 
   A(int i, double d) {
   }
 
   method() {}
 }
 main() {
   new A(1, 2.0);
 }
 ''');
   }
 
-  void test_createConstructor_named() {
+  test_createConstructor_named() async {
     resolveTestUnit('''
 class A {
   method() {}
 }
 main() {
   new A.named(1, 2.0);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_CONSTRUCTOR,
         '''
 class A {
   A.named(int i, double d) {
   }
 
   method() {}
 }
 main() {
   new A.named(1, 2.0);
 }
 ''');
     _assertLinkedGroup(change.linkedEditGroups[0], ['named(int ', 'named(1']);
   }
 
-  void test_createConstructorForFinalFields_inTopLevelMethod() {
+  test_createConstructorForFinalFields_inTopLevelMethod() async {
     resolveTestUnit('''
 main() {
   final int v;
 }
 ''');
-    assertNoFix(DartFixKind.CREATE_CONSTRUCTOR_FOR_FINAL_FIELDS);
+    await assertNoFix(DartFixKind.CREATE_CONSTRUCTOR_FOR_FINAL_FIELDS);
   }
 
-  void test_createConstructorForFinalFields_topLevelField() {
+  test_createConstructorForFinalFields_topLevelField() async {
     resolveTestUnit('''
 final int v;
 ''');
-    assertNoFix(DartFixKind.CREATE_CONSTRUCTOR_FOR_FINAL_FIELDS);
+    await assertNoFix(DartFixKind.CREATE_CONSTRUCTOR_FOR_FINAL_FIELDS);
   }
 
-  void test_createConstructorSuperExplicit() {
+  test_createConstructorSuperExplicit() async {
     resolveTestUnit('''
 class A {
   A(bool p1, int p2, double p3, String p4, {p5});
 }
 class B extends A {
   B() {}
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_SUPER_CONSTRUCTOR_INVOCATION,
         '''
 class A {
   A(bool p1, int p2, double p3, String p4, {p5});
 }
 class B extends A {
   B() : super(false, 0, 0.0, '') {}
 }
 ''');
   }
 
-  void test_createConstructorSuperExplicit_hasInitializers() {
+  test_createConstructorSuperExplicit_hasInitializers() async {
     resolveTestUnit('''
 class A {
   A(int p);
 }
 class B extends A {
   int field;
   B() : field = 42 {}
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_SUPER_CONSTRUCTOR_INVOCATION,
         '''
 class A {
   A(int p);
 }
 class B extends A {
   int field;
   B() : field = 42, super(0) {}
 }
 ''');
   }
 
-  void test_createConstructorSuperExplicit_named() {
+  test_createConstructorSuperExplicit_named() async {
     resolveTestUnit('''
 class A {
   A.named(int p);
 }
 class B extends A {
   B() {}
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_SUPER_CONSTRUCTOR_INVOCATION,
         '''
 class A {
   A.named(int p);
 }
 class B extends A {
   B() : super.named(0) {}
 }
 ''');
   }
 
-  void test_createConstructorSuperExplicit_named_private() {
+  test_createConstructorSuperExplicit_named_private() async {
     resolveTestUnit('''
 class A {
   A._named(int p);
 }
 class B extends A {
   B() {}
 }
 ''');
-    assertNoFix(DartFixKind.ADD_SUPER_CONSTRUCTOR_INVOCATION);
+    await assertNoFix(DartFixKind.ADD_SUPER_CONSTRUCTOR_INVOCATION);
   }
 
-  void test_createConstructorSuperExplicit_typeArgument() {
+  test_createConstructorSuperExplicit_typeArgument() async {
     resolveTestUnit('''
 class A<T> {
   A(T p);
 }
 class B extends A<int> {
   B();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_SUPER_CONSTRUCTOR_INVOCATION,
         '''
 class A<T> {
   A(T p);
 }
 class B extends A<int> {
   B() : super(0);
 }
 ''');
   }
 
-  void test_createConstructorSuperImplicit() {
+  test_createConstructorSuperImplicit() async {
     resolveTestUnit('''
 class A {
   A(p1, int p2, List<String> p3, [int p4]);
 }
 class B extends A {
   int existingField;
 
   void existingMethod() {}
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_CONSTRUCTOR_SUPER,
         '''
 class A {
   A(p1, int p2, List<String> p3, [int p4]);
 }
 class B extends A {
   int existingField;
 
   B(p1, int p2, List<String> p3) : super(p1, p2, p3);
 
   void existingMethod() {}
 }
 ''');
   }
 
-  void test_createConstructorSuperImplicit_fieldInitializer() {
+  test_createConstructorSuperImplicit_fieldInitializer() async {
     resolveTestUnit('''
 class A {
   int _field;
   A(this._field);
 }
 class B extends A {
   int existingField;
 
   void existingMethod() {}
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_CONSTRUCTOR_SUPER,
         '''
 class A {
   int _field;
   A(this._field);
 }
 class B extends A {
   int existingField;
 
   B(int field) : super(field);
 
   void existingMethod() {}
 }
 ''');
   }
 
-  void test_createConstructorSuperImplicit_importType() {
+  test_createConstructorSuperImplicit_importType() async {
     addSource(
         '/libA.dart',
         r'''
 library libA;
 class A {}
 ''');
     addSource(
         '/libB.dart',
         r'''
 library libB;
 import 'libA.dart';
 class B {
   B(A a);
 }
 ''');
     resolveTestUnit('''
 import 'libB.dart';
 class C extends B {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_CONSTRUCTOR_SUPER,
         '''
 import 'libB.dart';
 import 'libA.dart';
 class C extends B {
   C(A a) : super(a);
 }
 ''');
   }
 
-  void test_createConstructorSuperImplicit_named() {
+  test_createConstructorSuperImplicit_named() async {
     resolveTestUnit('''
 class A {
   A.named(p1, int p2);
 }
 class B extends A {
   int existingField;
 
   void existingMethod() {}
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_CONSTRUCTOR_SUPER,
         '''
 class A {
   A.named(p1, int p2);
 }
 class B extends A {
   int existingField;
 
   B.named(p1, int p2) : super.named(p1, p2);
 
   void existingMethod() {}
 }
 ''');
   }
 
-  void test_createConstructorSuperImplicit_private() {
+  test_createConstructorSuperImplicit_private() async {
     resolveTestUnit('''
 class A {
   A._named(p);
 }
 class B extends A {
 }
 ''');
-    assertNoFix(DartFixKind.CREATE_CONSTRUCTOR_SUPER);
+    await assertNoFix(DartFixKind.CREATE_CONSTRUCTOR_SUPER);
   }
 
-  void test_createConstructorSuperImplicit_typeArgument() {
+  test_createConstructorSuperImplicit_typeArgument() async {
     resolveTestUnit('''
 class C<T> {
   final T x;
   C(this.x);
 }
 class D extends C<int> {
 }''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_CONSTRUCTOR_SUPER,
         '''
 class C<T> {
   final T x;
   C(this.x);
 }
 class D extends C<int> {
   D(int x) : super(x);
 }''');
   }
 
-  void test_createField_BAD_inEnum() {
+  test_createField_BAD_inEnum() async {
     resolveTestUnit('''
 enum MyEnum {
   AAA, BBB
 }
 main() {
   MyEnum.foo;
 }
 ''');
-    assertNoFix(DartFixKind.CREATE_FIELD);
+    await assertNoFix(DartFixKind.CREATE_FIELD);
   }
 
-  void test_createField_BAD_inSDK() {
+  test_createField_BAD_inSDK() async {
     resolveTestUnit('''
 main(List p) {
   p.foo = 1;
 }
 ''');
-    assertNoFix(DartFixKind.CREATE_FIELD);
+    await assertNoFix(DartFixKind.CREATE_FIELD);
   }
 
-  void test_createField_getter_multiLevel() {
+  test_createField_getter_multiLevel() async {
     resolveTestUnit('''
 class A {
 }
 class B {
   A a;
 }
 class C {
   B b;
 }
 main(C c) {
   int v = c.b.a.test;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   int test;
 }
 class B {
   A a;
 }
 class C {
   B b;
 }
 main(C c) {
   int v = c.b.a.test;
 }
 ''');
   }
 
-  void test_createField_getter_qualified_instance() {
+  test_createField_getter_qualified_instance() async {
     resolveTestUnit('''
 class A {
 }
 main(A a) {
   int v = a.test;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   int test;
 }
 main(A a) {
   int v = a.test;
 }
 ''');
   }
 
-  void test_createField_getter_qualified_instance_dynamicType() {
+  test_createField_getter_qualified_instance_dynamicType() async {
     resolveTestUnit('''
 class A {
   B b;
   void f(Object p) {
     p == b.test;
   }
 }
 class B {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   B b;
   void f(Object p) {
     p == b.test;
   }
 }
 class B {
   var test;
 }
 ''');
   }
 
-  void test_createField_getter_unqualified_instance_asInvocationArgument() {
+  test_createField_getter_unqualified_instance_asInvocationArgument() async {
     resolveTestUnit('''
 class A {
   main() {
     f(test);
   }
 }
 f(String s) {}
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   String test;
 
   main() {
     f(test);
   }
 }
 f(String s) {}
 ''');
   }
 
-  void test_createField_getter_unqualified_instance_assignmentRhs() {
+  test_createField_getter_unqualified_instance_assignmentRhs() async {
     resolveTestUnit('''
 class A {
   main() {
     int v = test;
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   int test;
 
   main() {
     int v = test;
   }
 }
 ''');
   }
 
-  void test_createField_getter_unqualified_instance_asStatement() {
+  test_createField_getter_unqualified_instance_asStatement() async {
     resolveTestUnit('''
 class A {
   main() {
     test;
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   var test;
 
   main() {
     test;
   }
 }
 ''');
   }
 
-  void test_createField_hint() {
+  test_createField_hint() async {
     resolveTestUnit('''
 class A {
 }
 main(A a) {
   var x = a;
   int v = x.test;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   int test;
 }
 main(A a) {
   var x = a;
   int v = x.test;
 }
 ''');
   }
 
-  void test_createField_hint_setter() {
+  test_createField_hint_setter() async {
     resolveTestUnit('''
 class A {
 }
 main(A a) {
   var x = a;
   x.test = 0;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   int test;
 }
 main(A a) {
   var x = a;
   x.test = 0;
 }
 ''');
   }
 
-  void test_createField_importType() {
+  test_createField_importType() async {
     addSource(
         '/libA.dart',
         r'''
 library libA;
 class A {}
 ''');
     addSource(
         '/libB.dart',
         r'''
 library libB;
 import 'libA.dart';
 A getA() => null;
 ''');
     resolveTestUnit('''
 import 'libB.dart';
 class C {
 }
 main(C c) {
   c.test = getA();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 import 'libB.dart';
 import 'libA.dart';
 class C {
   A test;
 }
 main(C c) {
   c.test = getA();
 }
 ''');
   }
 
-  void test_createField_setter_generic_BAD() {
+  test_createField_setter_generic_BAD() async {
     resolveTestUnit('''
 class A {
 }
 class B<T> {
   List<T> items;
   main(A a) {
     a.test = items;
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   List test;
 }
 class B<T> {
   List<T> items;
   main(A a) {
     a.test = items;
   }
 }
 ''');
   }
 
-  void test_createField_setter_generic_OK_local() {
+  test_createField_setter_generic_OK_local() async {
     resolveTestUnit('''
 class A<T> {
   List<T> items;
 
   main(A a) {
     test = items;
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A<T> {
   List<T> items;
 
   List<T> test;
 
   main(A a) {
     test = items;
   }
 }
 ''');
   }
 
-  void test_createField_setter_qualified_instance_hasField() {
+  test_createField_setter_qualified_instance_hasField() async {
     resolveTestUnit('''
 class A {
   int aaa;
   int zzz;
 
   existingMethod() {}
 }
 main(A a) {
   a.test = 5;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   int aaa;
   int zzz;
 
   int test;
 
   existingMethod() {}
 }
 main(A a) {
   a.test = 5;
 }
 ''');
   }
 
-  void test_createField_setter_qualified_instance_hasMethod() {
+  test_createField_setter_qualified_instance_hasMethod() async {
     resolveTestUnit('''
 class A {
   existingMethod() {}
 }
 main(A a) {
   a.test = 5;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   int test;
 
   existingMethod() {}
 }
 main(A a) {
   a.test = 5;
 }
 ''');
   }
 
-  void test_createField_setter_qualified_static() {
+  test_createField_setter_qualified_static() async {
     resolveTestUnit('''
 class A {
 }
 main() {
   A.test = 5;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   static int test;
 }
 main() {
   A.test = 5;
 }
 ''');
   }
 
-  void test_createField_setter_unqualified_instance() {
+  test_createField_setter_unqualified_instance() async {
     resolveTestUnit('''
 class A {
   main() {
     test = 5;
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   int test;
 
   main() {
     test = 5;
   }
 }
 ''');
   }
 
-  void test_createField_setter_unqualified_static() {
+  test_createField_setter_unqualified_static() async {
     resolveTestUnit('''
 class A {
   static main() {
     test = 5;
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FIELD,
         '''
 class A {
   static int test;
 
   static main() {
     test = 5;
   }
 }
 ''');
   }
 
-  void test_createFile_forImport() {
+  test_createFile_forImport() async {
     testFile = '/my/project/bin/test.dart';
     resolveTestUnit('''
 import 'my_file.dart';
 ''');
     AnalysisError error = _findErrorToFix();
-    fix = _assertHasFix(DartFixKind.CREATE_FILE, error);
+    fix = await _assertHasFix(DartFixKind.CREATE_FILE, error);
     change = fix.change;
     // validate change
     List<SourceFileEdit> fileEdits = change.edits;
     expect(fileEdits, hasLength(1));
     SourceFileEdit fileEdit = change.edits[0];
     expect(fileEdit.file, '/my/project/bin/my_file.dart');
     expect(fileEdit.fileStamp, -1);
     expect(fileEdit.edits, hasLength(1));
     expect(fileEdit.edits[0].replacement, contains('library my_file;'));
   }
 
-  void test_createFile_forImport_inPackage_lib() {
+  test_createFile_forImport_inPackage_lib() async {
     provider.newFile('/projects/my_package/pubspec.yaml', 'name: my_package');
     testFile = '/projects/my_package/lib/test.dart';
     provider.newFolder('/projects/my_package/lib');
     resolveTestUnit('''
 import 'a/bb/c_cc/my_lib.dart';
 ''');
     AnalysisError error = _findErrorToFix();
-    fix = _assertHasFix(DartFixKind.CREATE_FILE, error);
+    fix = await _assertHasFix(DartFixKind.CREATE_FILE, error);
     change = fix.change;
     // validate change
     List<SourceFileEdit> fileEdits = change.edits;
     expect(fileEdits, hasLength(1));
     SourceFileEdit fileEdit = change.edits[0];
     expect(fileEdit.file, '/projects/my_package/lib/a/bb/c_cc/my_lib.dart');
     expect(fileEdit.fileStamp, -1);
     expect(fileEdit.edits, hasLength(1));
     expect(fileEdit.edits[0].replacement,
         contains('library my_package.a.bb.c_cc.my_lib;'));
   }
 
-  void test_createFile_forImport_inPackage_test() {
+  test_createFile_forImport_inPackage_test() async {
     provider.newFile('/projects/my_package/pubspec.yaml', 'name: my_package');
     testFile = '/projects/my_package/test/misc/test_all.dart';
     resolveTestUnit('''
 import 'a/bb/my_lib.dart';
 ''');
     AnalysisError error = _findErrorToFix();
-    fix = _assertHasFix(DartFixKind.CREATE_FILE, error);
+    fix = await _assertHasFix(DartFixKind.CREATE_FILE, error);
     change = fix.change;
     // validate change
     List<SourceFileEdit> fileEdits = change.edits;
     expect(fileEdits, hasLength(1));
     SourceFileEdit fileEdit = change.edits[0];
     expect(fileEdit.file, '/projects/my_package/test/misc/a/bb/my_lib.dart');
     expect(fileEdit.fileStamp, -1);
     expect(fileEdit.edits, hasLength(1));
     expect(fileEdit.edits[0].replacement,
         contains('library my_package.test.misc.a.bb.my_lib;'));
   }
 
-  void test_createFile_forPart() {
+  test_createFile_forPart() async {
     testFile = '/my/project/bin/test.dart';
     resolveTestUnit('''
 library my.lib;
 part 'my_part.dart';
 ''');
     AnalysisError error = _findErrorToFix();
-    fix = _assertHasFix(DartFixKind.CREATE_FILE, error);
+    fix = await _assertHasFix(DartFixKind.CREATE_FILE, error);
     change = fix.change;
     // validate change
     List<SourceFileEdit> fileEdits = change.edits;
     expect(fileEdits, hasLength(1));
     SourceFileEdit fileEdit = change.edits[0];
     expect(fileEdit.file, '/my/project/bin/my_part.dart');
     expect(fileEdit.fileStamp, -1);
     expect(fileEdit.edits, hasLength(1));
     expect(fileEdit.edits[0].replacement, contains('part of my.lib;'));
   }
 
-  void test_createFile_forPart_inPackageLib() {
+  test_createFile_forPart_inPackageLib() async {
     provider.newFile(
         '/my/pubspec.yaml',
         r'''
 name: my_test
 ''');
     testFile = '/my/lib/test.dart';
     addTestSource(
         '''
 library my.lib;
 part 'my_part.dart';
 ''',
         Uri.parse('package:my/test.dart'));
     // configure SourceFactory
     UriResolver pkgResolver = new PackageMapUriResolver(provider, {
       'my': [provider.getResource('/my/lib')],
     });
     context.sourceFactory = new SourceFactory(
         [AbstractContextTest.SDK_RESOLVER, pkgResolver, resourceResolver]);
     // prepare fix
     testUnit = resolveLibraryUnit(testSource);
     AnalysisError error = _findErrorToFix();
-    fix = _assertHasFix(DartFixKind.CREATE_FILE, error);
+    fix = await _assertHasFix(DartFixKind.CREATE_FILE, error);
     change = fix.change;
     // validate change
     List<SourceFileEdit> fileEdits = change.edits;
     expect(fileEdits, hasLength(1));
     SourceFileEdit fileEdit = change.edits[0];
     expect(fileEdit.file, '/my/lib/my_part.dart');
     expect(fileEdit.fileStamp, -1);
     expect(fileEdit.edits, hasLength(1));
     expect(fileEdit.edits[0].replacement, contains('part of my.lib;'));
   }
 
-  void test_createGetter_BAD_inSDK() {
+  test_createGetter_BAD_inSDK() async {
     resolveTestUnit('''
 main(List p) {
   int v = p.foo;
 }
 ''');
-    assertNoFix(DartFixKind.CREATE_GETTER);
+    await assertNoFix(DartFixKind.CREATE_GETTER);
   }
 
-  void test_createGetter_hint_getter() {
+  test_createGetter_hint_getter() async {
     resolveTestUnit('''
 class A {
 }
 main(A a) {
   var x = a;
   int v = x.test;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_GETTER,
         '''
 class A {
   int get test => null;
 }
 main(A a) {
   var x = a;
   int v = x.test;
 }
 ''');
   }
 
-  void test_createGetter_location_afterLastGetter() {
+  test_createGetter_location_afterLastGetter() async {
     resolveTestUnit('''
 class A {
   int existingField;
 
   int get existingGetter => null;
 
   existingMethod() {}
 }
 main(A a) {
   int v = a.test;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_GETTER,
         '''
 class A {
   int existingField;
 
   int get existingGetter => null;
 
   int get test => null;
 
   existingMethod() {}
 }
 main(A a) {
   int v = a.test;
 }
 ''');
   }
 
-  void test_createGetter_multiLevel() {
+  test_createGetter_multiLevel() async {
     resolveTestUnit('''
 class A {
 }
 class B {
   A a;
 }
 class C {
   B b;
 }
 main(C c) {
   int v = c.b.a.test;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_GETTER,
         '''
 class A {
   int get test => null;
 }
 class B {
   A a;
 }
 class C {
   B b;
 }
 main(C c) {
   int v = c.b.a.test;
 }
 ''');
   }
 
-  void test_createGetter_qualified_instance() {
+  test_createGetter_qualified_instance() async {
     resolveTestUnit('''
 class A {
 }
 main(A a) {
   int v = a.test;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_GETTER,
         '''
 class A {
   int get test => null;
 }
 main(A a) {
   int v = a.test;
 }
 ''');
   }
 
-  void test_createGetter_qualified_instance_dynamicType() {
+  test_createGetter_qualified_instance_dynamicType() async {
     resolveTestUnit('''
 class A {
   B b;
   void f(Object p) {
     p == b.test;
   }
 }
 class B {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_GETTER,
         '''
 class A {
   B b;
   void f(Object p) {
     p == b.test;
   }
 }
 class B {
   get test => null;
 }
 ''');
   }
 
-  void test_createGetter_setterContext() {
+  test_createGetter_setterContext() async {
     resolveTestUnit('''
 class A {
 }
 main(A a) {
   a.test = 42;
 }
 ''');
-    assertNoFix(DartFixKind.CREATE_GETTER);
+    await assertNoFix(DartFixKind.CREATE_GETTER);
   }
 
-  void test_createGetter_unqualified_instance_asInvocationArgument() {
+  test_createGetter_unqualified_instance_asInvocationArgument() async {
     resolveTestUnit('''
 class A {
   main() {
     f(test);
   }
 }
 f(String s) {}
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_GETTER,
         '''
 class A {
   String get test => null;
 
   main() {
     f(test);
   }
 }
 f(String s) {}
 ''');
   }
 
-  void test_createGetter_unqualified_instance_assignmentLhs() {
+  test_createGetter_unqualified_instance_assignmentLhs() async {
     resolveTestUnit('''
 class A {
   main() {
     test = 42;
   }
 }
 ''');
-    assertNoFix(DartFixKind.CREATE_GETTER);
+    await assertNoFix(DartFixKind.CREATE_GETTER);
   }
 
-  void test_createGetter_unqualified_instance_assignmentRhs() {
+  test_createGetter_unqualified_instance_assignmentRhs() async {
     resolveTestUnit('''
 class A {
   main() {
     int v = test;
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_GETTER,
         '''
 class A {
   int get test => null;
 
   main() {
     int v = test;
   }
 }
 ''');
   }
 
-  void test_createGetter_unqualified_instance_asStatement() {
+  test_createGetter_unqualified_instance_asStatement() async {
     resolveTestUnit('''
 class A {
   main() {
     test;
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_GETTER,
         '''
 class A {
   get test => null;
 
   main() {
     test;
   }
 }
 ''');
   }
 
-  void test_createLocalVariable_functionType_named() {
+  test_createLocalVariable_functionType_named() async {
     resolveTestUnit('''
 typedef MY_FUNCTION(int p);
 foo(MY_FUNCTION f) {}
 main() {
   foo(bar);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_LOCAL_VARIABLE,
         '''
 typedef MY_FUNCTION(int p);
 foo(MY_FUNCTION f) {}
 main() {
   MY_FUNCTION bar;
   foo(bar);
 }
 ''');
   }
 
-  void test_createLocalVariable_functionType_synthetic() {
+  test_createLocalVariable_functionType_synthetic() async {
     resolveTestUnit('''
 foo(f(int p)) {}
 main() {
   foo(bar);
 }
 ''');
-    assertNoFix(DartFixKind.CREATE_LOCAL_VARIABLE);
+    await assertNoFix(DartFixKind.CREATE_LOCAL_VARIABLE);
   }
 
-  void test_createLocalVariable_read_typeAssignment() {
+  test_createLocalVariable_read_typeAssignment() async {
     resolveTestUnit('''
 main() {
   int a = test;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_LOCAL_VARIABLE,
         '''
 main() {
   int test;
   int a = test;
 }
 ''');
   }
 
-  void test_createLocalVariable_read_typeCondition() {
+  test_createLocalVariable_read_typeCondition() async {
     resolveTestUnit('''
 main() {
   if (!test) {
     print(42);
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_LOCAL_VARIABLE,
         '''
 main() {
   bool test;
   if (!test) {
     print(42);
   }
 }
 ''');
   }
 
-  void test_createLocalVariable_read_typeInvocationArgument() {
+  test_createLocalVariable_read_typeInvocationArgument() async {
     resolveTestUnit('''
 main() {
   f(test);
 }
 f(String p) {}
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_LOCAL_VARIABLE,
         '''
 main() {
   String test;
   f(test);
 }
 f(String p) {}
 ''');
     _assertLinkedGroup(change.linkedEditGroups[0], ['String test;']);
     _assertLinkedGroup(change.linkedEditGroups[1], ['test;', 'test);']);
   }
 
-  void test_createLocalVariable_read_typeInvocationTarget() {
+  test_createLocalVariable_read_typeInvocationTarget() async {
     resolveTestUnit('''
 main() {
   test.add('hello');
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_LOCAL_VARIABLE,
         '''
 main() {
   var test;
   test.add('hello');
 }
 ''');
     _assertLinkedGroup(change.linkedEditGroups[0], ['test;', 'test.add(']);
   }
 
-  void test_createLocalVariable_write_assignment() {
+  test_createLocalVariable_write_assignment() async {
     resolveTestUnit('''
 main() {
   test = 42;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_LOCAL_VARIABLE,
         '''
 main() {
   var test = 42;
 }
 ''');
   }
 
-  void test_createLocalVariable_write_assignment_compound() {
+  test_createLocalVariable_write_assignment_compound() async {
     resolveTestUnit('''
 main() {
   test += 42;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_LOCAL_VARIABLE,
         '''
 main() {
   int test;
   test += 42;
 }
 ''');
   }
 
-  void test_createMissingOverrides_functionTypeAlias() {
+  test_createMissingOverrides_functionTypeAlias() async {
     resolveTestUnit('''
 typedef int Binary(int left, int right);
 
 abstract class Emulator {
   void performBinary(Binary binary);
 }
 
 class MyEmulator extends Emulator {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_MISSING_OVERRIDES,
         '''
 typedef int Binary(int left, int right);
 
 abstract class Emulator {
   void performBinary(Binary binary);
 }
 
 class MyEmulator extends Emulator {
   @override
   void performBinary(Binary binary) {
     // TODO: implement performBinary
   }
 }
 ''');
   }
 
-  void test_createMissingOverrides_functionTypedParameter() {
+  test_createMissingOverrides_functionTypedParameter() async {
     resolveTestUnit('''
 abstract class A {
   forEach(int f(double p1, String p2));
 }
 
 class B extends A {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_MISSING_OVERRIDES,
         '''
 abstract class A {
   forEach(int f(double p1, String p2));
 }
 
 class B extends A {
   @override
   forEach(int f(double p1, String p2)) {
     // TODO: implement forEach
   }
 }
 ''');
   }
 
-  void test_createMissingOverrides_generics_typeArguments() {
+  test_createMissingOverrides_generics_typeArguments() async {
     resolveTestUnit('''
 class Iterator<T> {
 }
 
 abstract class IterableMixin<T> {
   Iterator<T> get iterator;
 }
 
 class Test extends IterableMixin<int> {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_MISSING_OVERRIDES,
         '''
 class Iterator<T> {
 }
 
 abstract class IterableMixin<T> {
   Iterator<T> get iterator;
 }
 
 class Test extends IterableMixin<int> {
   // TODO: implement iterator
   @override
   Iterator<int> get iterator => null;
 }
 ''');
   }
 
-  void test_createMissingOverrides_generics_typeParameters() {
+  test_createMissingOverrides_generics_typeParameters() async {
     resolveTestUnit('''
 abstract class ItemProvider<T> {
   List<T> getItems();
 }
 
 class Test<V> extends ItemProvider<V> {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_MISSING_OVERRIDES,
         '''
 abstract class ItemProvider<T> {
   List<T> getItems();
 }
 
 class Test<V> extends ItemProvider<V> {
   @override
   List<V> getItems() {
     // TODO: implement getItems
   }
 }
 ''');
   }
 
-  void test_createMissingOverrides_getter() {
+  test_createMissingOverrides_getter() async {
     resolveTestUnit('''
 abstract class A {
   get g1;
   int get g2;
 }
 
 class B extends A {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_MISSING_OVERRIDES,
         '''
 abstract class A {
   get g1;
   int get g2;
 }
 
 class B extends A {
   // TODO: implement g1
   @override
   get g1 => null;
 
   // TODO: implement g2
   @override
   int get g2 => null;
 }
 ''');
   }
 
-  void test_createMissingOverrides_importPrefix() {
+  test_createMissingOverrides_importPrefix() async {
     resolveTestUnit('''
 import 'dart:async' as aaa;
 abstract class A {
   Map<aaa.Future, List<aaa.Future>> g(aaa.Future p);
 }
 
 class B extends A {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_MISSING_OVERRIDES,
         '''
 import 'dart:async' as aaa;
 abstract class A {
   Map<aaa.Future, List<aaa.Future>> g(aaa.Future p);
 }
 
 class B extends A {
   @override
   Map<aaa.Future, List<aaa.Future>> g(aaa.Future p) {
     // TODO: implement g
   }
 }
 ''');
   }
 
-  void test_createMissingOverrides_mergeToField_getterSetter() {
+  test_createMissingOverrides_mergeToField_getterSetter() async {
     resolveTestUnit('''
 class A {
   int ma;
   void mb() {}
   double mc;
 }
 
 class B implements A {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_MISSING_OVERRIDES,
         '''
 class A {
   int ma;
   void mb() {}
   double mc;
 }
 
 class B implements A {
   int ma;
 
   double mc;
 
   @override
   void mb() {
     // TODO: implement mb
   }
 }
 ''');
   }
 
-  void test_createMissingOverrides_method() {
+  test_createMissingOverrides_method() async {
     resolveTestUnit('''
 abstract class A {
   m1();
   int m2();
   String m3(int p1, double p2, Map<int, List<String>> p3);
   String m4(p1, p2);
   String m5(p1, [int p2 = 2, int p3, p4 = 4]);
   String m6(p1, {int p2: 2, int p3, p4: 4});
 }
 
@@ skipping 35 matching lines @@
   String m5(p1, [int p2 = 2, int p3, p4 = 4]) {
     // TODO: implement m5
   }
 
   @override
   String m6(p1, {int p2: 2, int p3, p4: 4}) {
     // TODO: implement m6
   }
 }
 ''';
-    assertHasFix(DartFixKind.CREATE_MISSING_OVERRIDES, expectedCode);
+    await assertHasFix(DartFixKind.CREATE_MISSING_OVERRIDES, expectedCode);
     // end position should be on "m1", not on "m2", "m3", etc
     {
       Position endPosition = change.selection;
       expect(endPosition, isNotNull);
       expect(endPosition.file, testFile);
       int endOffset = endPosition.offset;
       String endString = expectedCode.substring(endOffset, endOffset + 25);
       expect(endString, contains('m1'));
       expect(endString, isNot(contains('m2')));
       expect(endString, isNot(contains('m3')));
       expect(endString, isNot(contains('m4')));
       expect(endString, isNot(contains('m5')));
       expect(endString, isNot(contains('m6')));
     }
   }
 
-  void test_createMissingOverrides_operator() {
+  test_createMissingOverrides_operator() async {
     resolveTestUnit('''
 abstract class A {
   int operator [](int index);
   void operator []=(int index, String value);
 }
 
 class B extends A {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_MISSING_OVERRIDES,
         '''
 abstract class A {
   int operator [](int index);
   void operator []=(int index, String value);
 }
 
 class B extends A {
   @override
   int operator [](int index) {
     // TODO: implement []
   }
 
   @override
   void operator []=(int index, String value) {
     // TODO: implement []=
   }
 }
 ''');
   }
 
-  void test_createMissingOverrides_setter() {
+  test_createMissingOverrides_setter() async {
     resolveTestUnit('''
 abstract class A {
   set s1(x);
   set s2(int x);
   void set s3(String x);
 }
 
 class B extends A {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_MISSING_OVERRIDES,
         '''
 abstract class A {
   set s1(x);
   set s2(int x);
   void set s3(String x);
 }
 
 class B extends A {
   @override
   set s1(x) {
     // TODO: implement s1
   }
 
   @override
   set s2(int x) {
     // TODO: implement s2
   }
 
   @override
   void set s3(String x) {
     // TODO: implement s3
   }
 }
 ''');
   }
 
-  void test_createNoSuchMethod() {
+  test_createNoSuchMethod() async {
     resolveTestUnit('''
 abstract class A {
   m1();
   int m2();
 }
 
 class B extends A {
   existing() {}
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_NO_SUCH_METHOD,
         '''
 abstract class A {
   m1();
   int m2();
 }
 
 class B extends A {
   existing() {}
 
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 }
 ''');
   }
 
-  void test_creationFunction_forFunctionType_cascadeSecond() {
+  test_creationFunction_forFunctionType_cascadeSecond() async {
     resolveTestUnit('''
 class A {
   B ma() => null;
 }
 class B {
   useFunction(int g(double a, String b)) {}
 }
 
 main() {
   A a = new A();
   a..ma().useFunction(test);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 class A {
   B ma() => null;
 }
 class B {
   useFunction(int g(double a, String b)) {}
 }
 
 main() {
   A a = new A();
   a..ma().useFunction(test);
 }
 
 int test(double a, String b) {
 }
 ''');
   }
 
-  void test_creationFunction_forFunctionType_coreFunction() {
+  test_creationFunction_forFunctionType_coreFunction() async {
     resolveTestUnit('''
 main() {
   useFunction(g: test);
 }
 useFunction({Function g}) {}
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   useFunction(g: test);
 }
 useFunction({Function g}) {}
 
 test() {
 }
 ''');
   }
 
-  void test_creationFunction_forFunctionType_dynamicArgument() {
+  test_creationFunction_forFunctionType_dynamicArgument() async {
     resolveTestUnit('''
 main() {
   useFunction(test);
 }
 useFunction(int g(a, b)) {}
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   useFunction(test);
 }
 useFunction(int g(a, b)) {}
 
 int test(a, b) {
 }
 ''');
   }
 
-  void test_creationFunction_forFunctionType_function() {
+  test_creationFunction_forFunctionType_function() async {
     resolveTestUnit('''
 main() {
   useFunction(test);
 }
 useFunction(int g(double a, String b)) {}
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   useFunction(test);
 }
 useFunction(int g(double a, String b)) {}
 
 int test(double a, String b) {
 }
 ''');
   }
 
-  void test_creationFunction_forFunctionType_function_namedArgument() {
+  test_creationFunction_forFunctionType_function_namedArgument() async {
     resolveTestUnit('''
 main() {
   useFunction(g: test);
 }
 useFunction({int g(double a, String b)}) {}
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   useFunction(g: test);
 }
 useFunction({int g(double a, String b)}) {}
 
 int test(double a, String b) {
 }
 ''');
   }
 
-  void test_creationFunction_forFunctionType_importType() {
+  test_creationFunction_forFunctionType_importType() async {
     addSource(
         '/libA.dart',
         r'''
 library libA;
 class A {}
 ''');
     addSource(
         '/libB.dart',
         r'''
 library libB;
 import 'libA.dart';
 useFunction(int g(A a)) {}
 ''');
     resolveTestUnit('''
 import 'libB.dart';
 main() {
   useFunction(test);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 import 'libB.dart';
 import 'libA.dart';
 main() {
   useFunction(test);
 }
 
 int test(A a) {
 }
 ''');
   }
 
-  void test_creationFunction_forFunctionType_method_enclosingClass_static() {
+  test_creationFunction_forFunctionType_method_enclosingClass_static() async {
     resolveTestUnit('''
 class A {
   static foo() {
     useFunction(test);
   }
 }
 useFunction(int g(double a, String b)) {}
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A {
   static foo() {
     useFunction(test);
   }
 
   static int test(double a, String b) {
   }
 }
 useFunction(int g(double a, String b)) {}
 ''');
   }
 
-  void test_creationFunction_forFunctionType_method_enclosingClass_static2() {
+  test_creationFunction_forFunctionType_method_enclosingClass_static2() async {
     resolveTestUnit('''
 class A {
   var f;
   A() : f = useFunction(test);
 }
 useFunction(int g(double a, String b)) {}
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A {
   var f;
   A() : f = useFunction(test);
 
   static int test(double a, String b) {
   }
 }
 useFunction(int g(double a, String b)) {}
 ''');
   }
 
-  void test_creationFunction_forFunctionType_method_targetClass() {
+  test_creationFunction_forFunctionType_method_targetClass() async {
     resolveTestUnit('''
 main(A a) {
   useFunction(a.test);
 }
 class A {
 }
 useFunction(int g(double a, String b)) {}
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 main(A a) {
   useFunction(a.test);
 }
 class A {
   int test(double a, String b) {
   }
 }
 useFunction(int g(double a, String b)) {}
 ''');
   }
 
-  void test_creationFunction_forFunctionType_method_targetClass_hasOtherMember() {
+  test_creationFunction_forFunctionType_method_targetClass_hasOtherMember() async {
     resolveTestUnit('''
 main(A a) {
   useFunction(a.test);
 }
 class A {
   m() {}
 }
 useFunction(int g(double a, String b)) {}
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 main(A a) {
   useFunction(a.test);
 }
 class A {
   m() {}
 
   int test(double a, String b) {
   }
 }
 useFunction(int g(double a, String b)) {}
 ''');
   }
 
-  void test_creationFunction_forFunctionType_notFunctionType() {
+  test_creationFunction_forFunctionType_notFunctionType() async {
     resolveTestUnit('''
 main(A a) {
   useFunction(a.test);
 }
 typedef A();
 useFunction(g) {}
 ''');
-    assertNoFix(DartFixKind.CREATE_METHOD);
-    assertNoFix(DartFixKind.CREATE_FUNCTION);
+    await assertNoFix(DartFixKind.CREATE_METHOD);
+    await assertNoFix(DartFixKind.CREATE_FUNCTION);
   }
 
-  void test_creationFunction_forFunctionType_unknownTarget() {
+  test_creationFunction_forFunctionType_unknownTarget() async {
     resolveTestUnit('''
 main(A a) {
   useFunction(a.test);
 }
 class A {
 }
 useFunction(g) {}
 ''');
-    assertNoFix(DartFixKind.CREATE_METHOD);
+    await assertNoFix(DartFixKind.CREATE_METHOD);
   }
 
-  void test_expectedToken_semicolon() {
+  test_expectedToken_semicolon() async {
     resolveTestUnit('''
 main() {
   print(0)
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.INSERT_SEMICOLON,
         '''
 main() {
   print(0);
 }
 ''');
   }
 
-  void test_illegalAsyncReturnType_asyncLibrary_import() {
+  test_illegalAsyncReturnType_asyncLibrary_import() async {
     errorFilter = (AnalysisError error) {
       return error.errorCode == StaticTypeWarningCode.ILLEGAL_ASYNC_RETURN_TYPE;
     };
     resolveTestUnit('''
 library main;
 int main() async {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REPLACE_RETURN_TYPE_FUTURE,
         '''
 library main;
 import 'dart:async';
 Future<int> main() async {
 }
 ''');
   }
 
-  void test_illegalAsyncReturnType_asyncLibrary_usePrefix() {
+  test_illegalAsyncReturnType_asyncLibrary_usePrefix() async {
     errorFilter = (AnalysisError error) {
       return error.errorCode == StaticTypeWarningCode.ILLEGAL_ASYNC_RETURN_TYPE;
     };
     resolveTestUnit('''
 import 'dart:async' as al;
 int main() async {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REPLACE_RETURN_TYPE_FUTURE,
         '''
 import 'dart:async' as al;
 al.Future<int> main() async {
 }
 ''');
   }
 
-  void test_illegalAsyncReturnType_complexTypeName() {
+  test_illegalAsyncReturnType_complexTypeName() async {
     errorFilter = (AnalysisError error) {
       return error.errorCode == StaticTypeWarningCode.ILLEGAL_ASYNC_RETURN_TYPE;
     };
     resolveTestUnit('''
 import 'dart:async';
 List<int> main() async {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REPLACE_RETURN_TYPE_FUTURE,
         '''
 import 'dart:async';
 Future<List<int>> main() async {
 }
 ''');
   }
 
-  void test_illegalAsyncReturnType_void() {
+  test_illegalAsyncReturnType_void() async {
     errorFilter = (AnalysisError error) {
       return error.errorCode == StaticTypeWarningCode.ILLEGAL_ASYNC_RETURN_TYPE;
     };
     resolveTestUnit('''
 import 'dart:async';
 void main() async {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REPLACE_RETURN_TYPE_FUTURE,
         '''
 import 'dart:async';
 Future main() async {
 }
 ''');
   }
 
-  void test_importLibraryPackage_withClass() {
+  test_importLibraryPackage_withClass() async {
     _configureMyPkg('''
 library my_lib;
 class Test {}
 ''');
     // try to find a fix
     resolveTestUnit('''
 main() {
   Test test = null;
 }
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_PROJECT,
         '''
 import 'package:my_pkg/my_lib.dart';
 
 main() {
   Test test = null;
 }
 ''');
   }
 
-  void test_importLibraryProject_withClass_annotation() {
+  test_importLibraryProject_withClass_annotation() async {
     addSource(
         '/lib.dart',
         '''
 library lib;
 class Test {
   const Test(int p);
 }
 ''');
     resolveTestUnit('''
 @Test(0)
 main() {
 }
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_PROJECT,
         '''
 import 'lib.dart';
 
 @Test(0)
 main() {
 }
 ''');
   }
 
-  void test_importLibraryProject_withClass_hasOtherLibraryWithPrefix() {
+  test_importLibraryProject_withClass_hasOtherLibraryWithPrefix() async {
     testFile = '/project/bin/test.dart';
     addSource(
         '/project/bin/a.dart',
         '''
 library a;
 class One {}
 ''');
     addSource(
         '/project/bin/b.dart',
         '''
 library b;
 class One {}
 class Two {}
 ''');
     resolveTestUnit('''
 import 'b.dart' show Two;
 main () {
   new Two();
   new One();
 }
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_PROJECT,
         '''
 import 'b.dart' show Two;
 import 'a.dart';
 main () {
   new Two();
   new One();
 }
 ''');
   }
 
-  void test_importLibraryProject_withClass_inParentFolder() {
+  test_importLibraryProject_withClass_inParentFolder() async {
     testFile = '/project/bin/test.dart';
     addSource(
         '/project/lib.dart',
         '''
 library lib;
 class Test {}
 ''');
     resolveTestUnit('''
 main() {
   Test t = null;
 }
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_PROJECT,
         '''
 import '../lib.dart';
 
 main() {
   Test t = null;
 }
 ''');
   }
 
-  void test_importLibraryProject_withClass_inRelativeFolder() {
+  test_importLibraryProject_withClass_inRelativeFolder() async {
     testFile = '/project/bin/test.dart';
     addSource(
         '/project/lib/sub/folder/lib.dart',
         '''
 library lib;
 class Test {}
 ''');
     resolveTestUnit('''
 main() {
   Test t = null;
 }
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_PROJECT,
         '''
 import '../lib/sub/folder/lib.dart';
 
 main() {
   Test t = null;
 }
 ''');
   }
 
-  void test_importLibraryProject_withClass_inSameFolder() {
+  test_importLibraryProject_withClass_inSameFolder() async {
     testFile = '/project/bin/test.dart';
     addSource(
         '/project/bin/lib.dart',
         '''
 library lib;
 class Test {}
 ''');
     resolveTestUnit('''
 main() {
   Test t = null;
 }
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_PROJECT,
         '''
 import 'lib.dart';
 
 main() {
   Test t = null;
 }
 ''');
   }
 
-  void test_importLibraryProject_withFunction() {
+  test_importLibraryProject_withFunction() async {
     addSource(
         '/lib.dart',
         '''
 library lib;
 myFunction() {}
 ''');
     resolveTestUnit('''
 main() {
   myFunction();
 }
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_PROJECT,
         '''
 import 'lib.dart';
 
 main() {
   myFunction();
 }
 ''');
   }
 
-  void test_importLibraryProject_withFunction_unresolvedMethod() {
+  test_importLibraryProject_withFunction_unresolvedMethod() async {
     addSource(
         '/lib.dart',
         '''
 library lib;
 myFunction() {}
 ''');
     resolveTestUnit('''
 class A {
   main() {
     myFunction();
   }
 }
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_PROJECT,
         '''
 import 'lib.dart';
 
 class A {
   main() {
     myFunction();
   }
 }
 ''');
   }
 
-  void test_importLibraryProject_withFunctionTypeAlias() {
+  test_importLibraryProject_withFunctionTypeAlias() async {
     testFile = '/project/bin/test.dart';
     addSource(
         '/project/bin/lib.dart',
         '''
 library lib;
 typedef MyFunction();
 ''');
     resolveTestUnit('''
 main() {
   MyFunction t = null;
 }
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_PROJECT,
         '''
 import 'lib.dart';
 
 main() {
   MyFunction t = null;
 }
 ''');
   }
 
-  void test_importLibraryProject_withTopLevelVariable() {
+  test_importLibraryProject_withTopLevelVariable() async {
     addSource(
         '/lib.dart',
         '''
 library lib;
 int MY_VAR = 42;
 ''');
     resolveTestUnit('''
 main() {
   print(MY_VAR);
 }
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_PROJECT,
         '''
 import 'lib.dart';
 
 main() {
   print(MY_VAR);
 }
 ''');
   }
 
-  void test_importLibrarySdk_withClass_AsExpression() {
+  test_importLibrarySdk_withClass_AsExpression() async {
     resolveTestUnit('''
 main(p) {
   p as Future;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_SDK,
         '''
 import 'dart:async';
 
 main(p) {
   p as Future;
 }
 ''');
   }
 
-  void test_importLibrarySdk_withClass_invocationTarget() {
+  test_importLibrarySdk_withClass_invocationTarget() async {
     resolveTestUnit('''
 main() {
   Future.wait(null);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_SDK,
         '''
 import 'dart:async';
 
 main() {
   Future.wait(null);
 }
 ''');
   }
 
-  void test_importLibrarySdk_withClass_IsExpression() {
+  test_importLibrarySdk_withClass_IsExpression() async {
     resolveTestUnit('''
 main(p) {
   p is Future;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_SDK,
         '''
 import 'dart:async';
 
 main(p) {
   p is Future;
 }
 ''');
   }
 
-  void test_importLibrarySdk_withClass_itemOfList() {
+  test_importLibrarySdk_withClass_itemOfList() async {
     resolveTestUnit('''
 main() {
   var a = [Future];
 }
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_SDK,
         '''
 import 'dart:async';
 
 main() {
   var a = [Future];
 }
 ''');
   }
 
-  void test_importLibrarySdk_withClass_itemOfList_inAnnotation() {
+  test_importLibrarySdk_withClass_itemOfList_inAnnotation() async {
     errorFilter = (AnalysisError error) {
       return error.errorCode == StaticWarningCode.UNDEFINED_IDENTIFIER;
     };
     resolveTestUnit('''
 class MyAnnotation {
   const MyAnnotation(a, b);
 }
 @MyAnnotation(int, const [Future])
 main() {}
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_SDK,
         '''
 import 'dart:async';
 
 class MyAnnotation {
   const MyAnnotation(a, b);
 }
 @MyAnnotation(int, const [Future])
 main() {}
 ''');
   }
 
-  void test_importLibrarySdk_withClass_typeAnnotation() {
+  test_importLibrarySdk_withClass_typeAnnotation() async {
     resolveTestUnit('''
 main() {
   Future f = null;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_SDK,
         '''
 import 'dart:async';
 
 main() {
   Future f = null;
 }
 ''');
   }
 
-  void test_importLibrarySdk_withClass_typeAnnotation_PrefixedIdentifier() {
+  test_importLibrarySdk_withClass_typeAnnotation_PrefixedIdentifier() async {
     resolveTestUnit('''
 main() {
   Future.wait;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_SDK,
         '''
 import 'dart:async';
 
 main() {
   Future.wait;
 }
 ''');
   }
 
-  void test_importLibrarySdk_withClass_typeArgument() {
+  test_importLibrarySdk_withClass_typeArgument() async {
     resolveTestUnit('''
 main() {
   List<Future> futures = [];
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_SDK,
         '''
 import 'dart:async';
 
 main() {
   List<Future> futures = [];
 }
 ''');
   }
 
-  void test_importLibrarySdk_withTopLevelVariable() {
+  test_importLibrarySdk_withTopLevelVariable() async {
     resolveTestUnit('''
 main() {
   print(PI);
 }
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_SDK,
         '''
 import 'dart:math';
 
 main() {
   print(PI);
 }
 ''');
   }
 
-  void test_importLibrarySdk_withTopLevelVariable_annotation() {
+  test_importLibrarySdk_withTopLevelVariable_annotation() async {
     resolveTestUnit('''
 @PI
 main() {
 }
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_SDK,
         '''
 import 'dart:math';
 
 @PI
 main() {
 }
 ''');
   }
 
-  void test_importLibraryShow() {
+  test_importLibraryShow() async {
     resolveTestUnit('''
 import 'dart:async' show Stream;
 main() {
   Stream s = null;
   Future f = null;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_SHOW,
         '''
 import 'dart:async' show Future, Stream;
 main() {
   Stream s = null;
   Future f = null;
 }
 ''');
   }
 
-  void test_isNotNull() {
+  test_isNotNull() async {
     resolveTestUnit('''
 main(p) {
   p is! Null;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.USE_NOT_EQ_NULL,
         '''
 main(p) {
   p != null;
 }
 ''');
   }
 
-  void test_isNull() {
+  test_isNull() async {
     resolveTestUnit('''
 main(p) {
   p is Null;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.USE_EQ_EQ_NULL,
         '''
 main(p) {
   p == null;
 }
 ''');
   }
 
-  void test_makeEnclosingClassAbstract_declaresAbstractMethod() {
+  test_makeEnclosingClassAbstract_declaresAbstractMethod() async {
     resolveTestUnit('''
 class A {
   m();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.MAKE_CLASS_ABSTRACT,
         '''
 abstract class A {
   m();
 }
 ''');
   }
 
-  void test_makeEnclosingClassAbstract_inheritsAbstractMethod() {
+  test_makeEnclosingClassAbstract_inheritsAbstractMethod() async {
     resolveTestUnit('''
 abstract class A {
   m();
 }
 class B extends A {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.MAKE_CLASS_ABSTRACT,
         '''
 abstract class A {
   m();
 }
 abstract class B extends A {
 }
 ''');
   }
 
-  void test_noException_1() {
+  test_noException_1() async {
     resolveTestUnit('''
 main(p) {
   p i s Null;
 }''');
     List<AnalysisError> errors = context.computeErrors(testSource);
     for (var error in errors) {
-      _computeFixes(error);
+      await _computeFixes(error);
     }
   }
 
-  void test_nonBoolCondition_addNotNull() {
+  test_nonBoolCondition_addNotNull() async {
     resolveTestUnit('''
 main(String p) {
   if (p) {
     print(p);
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.ADD_NE_NULL,
         '''
 main(String p) {
   if (p != null) {
     print(p);
   }
 }
 ''');
   }
 
-  void test_removeDeadCode_condition() {
+  test_removeDeadCode_condition() async {
     resolveTestUnit('''
 main(int p) {
   if (true || p > 5) {
     print(1);
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REMOVE_DEAD_CODE,
         '''
 main(int p) {
   if (true) {
     print(1);
   }
 }
 ''');
   }
 
-  void test_removeDeadCode_statements_one() {
+  test_removeDeadCode_statements_one() async {
     resolveTestUnit('''
 int main() {
   print(0);
   return 42;
   print(1);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REMOVE_DEAD_CODE,
         '''
 int main() {
   print(0);
   return 42;
 }
 ''');
   }
 
-  void test_removeDeadCode_statements_two() {
+  test_removeDeadCode_statements_two() async {
     resolveTestUnit('''
 int main() {
   print(0);
   return 42;
   print(1);
   print(2);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REMOVE_DEAD_CODE,
         '''
 int main() {
   print(0);
   return 42;
 }
 ''');
   }
 
-  void test_removeParentheses_inGetterDeclaration() {
+  test_removeParentheses_inGetterDeclaration() async {
     resolveTestUnit('''
 class A {
   int get foo() => 0;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REMOVE_PARAMETERS_IN_GETTER_DECLARATION,
         '''
 class A {
   int get foo => 0;
 }
 ''');
   }
 
-  void test_removeParentheses_inGetterInvocation() {
+  test_removeParentheses_inGetterInvocation() async {
     resolveTestUnit('''
 class A {
   int get foo => 0;
 }
 main(A a) {
   a.foo();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REMOVE_PARENTHESIS_IN_GETTER_INVOCATION,
         '''
 class A {
   int get foo => 0;
 }
 main(A a) {
   a.foo;
 }
 ''');
   }
 
-  void test_removeUnnecessaryCast_assignment() {
+  test_removeUnnecessaryCast_assignment() async {
     resolveTestUnit('''
 main(Object p) {
   if (p is String) {
     String v = ((p as String));
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REMOVE_UNNECESSARY_CAST,
         '''
 main(Object p) {
   if (p is String) {
     String v = p;
   }
 }
 ''');
   }
 
-  void test_removeUnusedCatchClause() {
+  test_removeUnusedCatchClause() async {
     errorFilter = (AnalysisError error) => true;
     resolveTestUnit('''
 main() {
   try {
     throw 42;
   } on int catch (e) {
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REMOVE_UNUSED_CATCH_CLAUSE,
         '''
 main() {
   try {
     throw 42;
   } on int {
   }
 }
 ''');
   }
 
-  void test_removeUnusedCatchStack() {
+  test_removeUnusedCatchStack() async {
     errorFilter = (AnalysisError error) => true;
     resolveTestUnit('''
 main() {
   try {
     throw 42;
   } catch (e, stack) {
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REMOVE_UNUSED_CATCH_STACK,
         '''
 main() {
   try {
     throw 42;
   } catch (e) {
   }
 }
 ''');
   }
 
-  void test_removeUnusedImport() {
+  test_removeUnusedImport() async {
     resolveTestUnit('''
 import 'dart:math';
 main() {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REMOVE_UNUSED_IMPORT,
         '''
 main() {
 }
 ''');
   }
 
-  void test_removeUnusedImport_anotherImportOnLine() {
+  test_removeUnusedImport_anotherImportOnLine() async {
     resolveTestUnit('''
 import 'dart:math'; import 'dart:async';
 
 main() {
   Future f;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REMOVE_UNUSED_IMPORT,
         '''
 import 'dart:async';
 
 main() {
   Future f;
 }
 ''');
   }
 
-  void test_removeUnusedImport_severalLines() {
+  test_removeUnusedImport_severalLines() async {
     resolveTestUnit('''
 import
   'dart:math';
 main() {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REMOVE_UNUSED_IMPORT,
         '''
 main() {
 }
 ''');
   }
 
-  void test_replaceImportUri_inProject() {
+  test_replaceImportUri_inProject() async {
     testFile = '/project/bin/test.dart';
     addSource('/project/foo/bar/lib.dart', '');
     resolveTestUnit('''
 import 'no/matter/lib.dart';
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REPLACE_IMPORT_URI,
         '''
 import '../foo/bar/lib.dart';
 ''');
   }
 
-  void test_replaceImportUri_package() {
+  test_replaceImportUri_package() async {
     _configureMyPkg('');
     resolveTestUnit('''
 import 'no/matter/my_lib.dart';
 ''');
     performAllAnalysisTasks();
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REPLACE_IMPORT_URI,
         '''
 import 'package:my_pkg/my_lib.dart';
 ''');
   }
 
-  void test_replaceVarWithDynamic() {
+  test_replaceVarWithDynamic() async {
     errorFilter = (AnalysisError error) {
       return error.errorCode == ParserErrorCode.VAR_AS_TYPE_NAME;
     };
     resolveTestUnit('''
 class A {
   Map<String, var> m;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.REPLACE_VAR_WITH_DYNAMIC,
         '''
 class A {
   Map<String, dynamic> m;
 }
 ''');
   }
 
-  void test_replaceWithConstInstanceCreation() {
+  test_replaceWithConstInstanceCreation() async {
     resolveTestUnit('''
 class A {
   const A();
 }
 const a = new A();
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.USE_CONST,
         '''
 class A {
   const A();
 }
 const a = const A();
 ''');
   }
 
-  void test_undefinedClass_useSimilar_fromImport() {
+  test_undefinedClass_useSimilar_fromImport() async {
     resolveTestUnit('''
 main() {
   Stirng s = 'abc';
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 main() {
   String s = 'abc';
 }
 ''');
   }
 
-  void test_undefinedClass_useSimilar_fromThisLibrary() {
+  test_undefinedClass_useSimilar_fromThisLibrary() async {
     resolveTestUnit('''
 class MyClass {}
 main() {
   MyCalss v = null;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 class MyClass {}
 main() {
   MyClass v = null;
 }
 ''');
   }
 
-  void test_undefinedFunction_create_dynamicArgument() {
+  test_undefinedFunction_create_dynamicArgument() async {
     resolveTestUnit('''
 main() {
   dynamic v;
   test(v);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   dynamic v;
   test(v);
 }
 
 void test(v) {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_dynamicReturnType() {
+  test_undefinedFunction_create_dynamicReturnType() async {
     resolveTestUnit('''
 main() {
   dynamic v = test();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   dynamic v = test();
 }
 
 test() {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_fromFunction() {
+  test_undefinedFunction_create_fromFunction() async {
     resolveTestUnit('''
 main() {
   int v = myUndefinedFunction(1, 2.0, '3');
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   int v = myUndefinedFunction(1, 2.0, '3');
 }
 
 int myUndefinedFunction(int i, double d, String s) {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_fromMethod() {
+  test_undefinedFunction_create_fromMethod() async {
     resolveTestUnit('''
 class A {
   main() {
     int v = myUndefinedFunction(1, 2.0, '3');
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 class A {
   main() {
     int v = myUndefinedFunction(1, 2.0, '3');
   }
 }
 
 int myUndefinedFunction(int i, double d, String s) {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_generic_BAD() {
+  test_undefinedFunction_create_generic_BAD() async {
     resolveTestUnit('''
 class A<T> {
   Map<int, T> items;
   main() {
     process(items);
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 class A<T> {
   Map<int, T> items;
   main() {
     process(items);
   }
 }
 
 void process(Map items) {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_generic_OK() {
+  test_undefinedFunction_create_generic_OK() async {
     resolveTestUnit('''
 class A {
   List<int> items;
   main() {
     process(items);
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 class A {
   List<int> items;
   main() {
     process(items);
   }
 }
 
 void process(List<int> items) {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_importType() {
+  test_undefinedFunction_create_importType() async {
     addSource(
         '/lib.dart',
         r'''
 library lib;
 import 'dart:async';
 Future getFuture() => null;
 ''');
     resolveTestUnit('''
 import 'lib.dart';
 main() {
   test(getFuture());
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 import 'lib.dart';
 import 'dart:async';
 main() {
   test(getFuture());
 }
 
 void test(Future future) {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_nullArgument() {
+  test_undefinedFunction_create_nullArgument() async {
     resolveTestUnit('''
 main() {
   test(null);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   test(null);
 }
 
 void test(arg0) {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_returnType_bool_expressions() {
-    assert_undefinedFunction_create_returnType_bool("!test();");
-    assert_undefinedFunction_create_returnType_bool("b && test();");
-    assert_undefinedFunction_create_returnType_bool("test() && b;");
-    assert_undefinedFunction_create_returnType_bool("b || test();");
-    assert_undefinedFunction_create_returnType_bool("test() || b;");
+  test_undefinedFunction_create_returnType_bool_expressions() async {
+    await assert_undefinedFunction_create_returnType_bool("!test();");
+    await assert_undefinedFunction_create_returnType_bool("b && test();");
+    await assert_undefinedFunction_create_returnType_bool("test() && b;");
+    await assert_undefinedFunction_create_returnType_bool("b || test();");
+    await assert_undefinedFunction_create_returnType_bool("test() || b;");
   }
 
-  void test_undefinedFunction_create_returnType_bool_statements() {
-    assert_undefinedFunction_create_returnType_bool("assert ( test() );");
-    assert_undefinedFunction_create_returnType_bool("if ( test() ) {}");
-    assert_undefinedFunction_create_returnType_bool("while ( test() ) {}");
-    assert_undefinedFunction_create_returnType_bool("do {} while ( test() );");
+  test_undefinedFunction_create_returnType_bool_statements() async {
+    await assert_undefinedFunction_create_returnType_bool("assert ( test() );");
+    await assert_undefinedFunction_create_returnType_bool("if ( test() ) {}");
+    await assert_undefinedFunction_create_returnType_bool(
+        "while ( test() ) {}");
+    await assert_undefinedFunction_create_returnType_bool(
+        "do {} while ( test() );");
   }
 
-  void test_undefinedFunction_create_returnType_fromAssignment_eq() {
+  test_undefinedFunction_create_returnType_fromAssignment_eq() async {
     resolveTestUnit('''
 main() {
   int v;
   v = myUndefinedFunction();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   int v;
   v = myUndefinedFunction();
 }
 
 int myUndefinedFunction() {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_returnType_fromAssignment_plusEq() {
+  test_undefinedFunction_create_returnType_fromAssignment_plusEq() async {
     resolveTestUnit('''
 main() {
   int v;
   v += myUndefinedFunction();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   int v;
   v += myUndefinedFunction();
 }
 
 num myUndefinedFunction() {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_returnType_fromBinary_right() {
+  test_undefinedFunction_create_returnType_fromBinary_right() async {
     resolveTestUnit('''
 main() {
   0 + myUndefinedFunction();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   0 + myUndefinedFunction();
 }
 
 num myUndefinedFunction() {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_returnType_fromInitializer() {
+  test_undefinedFunction_create_returnType_fromInitializer() async {
     resolveTestUnit('''
 main() {
   int v = myUndefinedFunction();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   int v = myUndefinedFunction();
 }
 
 int myUndefinedFunction() {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_returnType_fromInvocationArgument() {
+  test_undefinedFunction_create_returnType_fromInvocationArgument() async {
     resolveTestUnit('''
 foo(int p) {}
 main() {
   foo( myUndefinedFunction() );
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 foo(int p) {}
 main() {
   foo( myUndefinedFunction() );
 }
 
 int myUndefinedFunction() {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_returnType_fromReturn() {
+  test_undefinedFunction_create_returnType_fromReturn() async {
     resolveTestUnit('''
 int main() {
   return myUndefinedFunction();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 int main() {
   return myUndefinedFunction();
 }
 
 int myUndefinedFunction() {
 }
 ''');
   }
 
-  void test_undefinedFunction_create_returnType_void() {
+  test_undefinedFunction_create_returnType_void() async {
     resolveTestUnit('''
 main() {
   myUndefinedFunction();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_FUNCTION,
         '''
 main() {
   myUndefinedFunction();
 }
 
 void myUndefinedFunction() {
 }
 ''');
   }
 
-  void test_undefinedFunction_useSimilar_fromImport() {
+  test_undefinedFunction_useSimilar_fromImport() async {
     resolveTestUnit('''
 main() {
   pritn(0);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 main() {
   print(0);
 }
 ''');
   }
 
-  void test_undefinedFunction_useSimilar_thisLibrary() {
+  test_undefinedFunction_useSimilar_thisLibrary() async {
     resolveTestUnit('''
 myFunction() {}
 main() {
   myFuntcion();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 myFunction() {}
 main() {
   myFunction();
 }
 ''');
   }
 
-  void test_undefinedGetter_useSimilar_hint() {
+  test_undefinedGetter_useSimilar_hint() async {
     resolveTestUnit('''
 class A {
   int myField;
 }
 main(A a) {
   var x = a;
   print(x.myFild);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 class A {
   int myField;
 }
 main(A a) {
   var x = a;
   print(x.myField);
 }
 ''');
   }
 
-  void test_undefinedGetter_useSimilar_qualified() {
+  test_undefinedGetter_useSimilar_qualified() async {
     resolveTestUnit('''
 class A {
   int myField;
 }
 main(A a) {
   print(a.myFild);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 class A {
   int myField;
 }
 main(A a) {
   print(a.myField);
 }
 ''');
   }
 
-  void test_undefinedGetter_useSimilar_qualified_static() {
+  test_undefinedGetter_useSimilar_qualified_static() async {
     resolveTestUnit('''
 class A {
   static int MY_NAME = 1;
 }
 main() {
   A.MY_NAM;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 class A {
   static int MY_NAME = 1;
 }
 main() {
   A.MY_NAME;
 }
 ''');
   }
 
-  void test_undefinedGetter_useSimilar_unqualified() {
+  test_undefinedGetter_useSimilar_unqualified() async {
     resolveTestUnit('''
 class A {
   int myField;
   main() {
     print(myFild);
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 class A {
   int myField;
   main() {
     print(myField);
   }
 }
 ''');
   }
 
-  void test_undefinedMethod_create_BAD_inSDK() {
+  test_undefinedMethod_create_BAD_inSDK() async {
     resolveTestUnit('''
 main() {
   List.foo();
 }
 ''');
-    assertNoFix(DartFixKind.CREATE_METHOD);
+    await assertNoFix(DartFixKind.CREATE_METHOD);
   }
 
-  void test_undefinedMethod_create_generic_BAD_argumentType() {
+  test_undefinedMethod_create_generic_BAD_argumentType() async {
     resolveTestUnit('''
 class A<T> {
   B b;
   Map<int, T> items;
   main() {
     b.process(items);
   }
 }
 
 class B {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A<T> {
   B b;
   Map<int, T> items;
   main() {
     b.process(items);
   }
 }
 
 class B {
   void process(Map items) {
   }
 }
 ''');
   }
 
-  void test_undefinedMethod_create_generic_BAD_returnType() {
+  test_undefinedMethod_create_generic_BAD_returnType() async {
     resolveTestUnit('''
 class A<T> {
   main() {
     T t = new B().compute();
   }
 }
 
 class B {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A<T> {
   main() {
     T t = new B().compute();
   }
 }
 
 class B {
   dynamic compute() {
   }
 }
 ''');
   }
 
-  void test_undefinedMethod_create_generic_OK_literal() {
+  test_undefinedMethod_create_generic_OK_literal() async {
     resolveTestUnit('''
 class A {
   B b;
   List<int> items;
   main() {
     b.process(items);
   }
 }
 
 class B {
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A {
   B b;
   List<int> items;
   main() {
     b.process(items);
   }
 }
 
 class B {
   void process(List<int> items) {
   }
 }
 ''');
   }
 
-  void test_undefinedMethod_create_generic_OK_local() {
+  test_undefinedMethod_create_generic_OK_local() async {
     resolveTestUnit('''
 class A<T> {
   List<T> items;
   main() {
     process(items);
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A<T> {
   List<T> items;
   main() {
     process(items);
   }
 
   void process(List<T> items) {
   }
 }
 ''');
   }
 
-  void test_undefinedMethod_createQualified_fromClass() {
+  test_undefinedMethod_createQualified_fromClass() async {
     resolveTestUnit('''
 class A {
 }
 main() {
   A.myUndefinedMethod();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A {
   static void myUndefinedMethod() {
   }
 }
 main() {
   A.myUndefinedMethod();
 }
 ''');
   }
 
-  void test_undefinedMethod_createQualified_fromClass_hasOtherMember() {
+  test_undefinedMethod_createQualified_fromClass_hasOtherMember() async {
     resolveTestUnit('''
 class A {
   foo() {}
 }
 main() {
   A.myUndefinedMethod();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A {
   foo() {}
 
   static void myUndefinedMethod() {
   }
 }
 main() {
   A.myUndefinedMethod();
 }
 ''');
   }
 
-  void test_undefinedMethod_createQualified_fromInstance() {
+  test_undefinedMethod_createQualified_fromInstance() async {
     resolveTestUnit('''
 class A {
 }
 main(A a) {
   a.myUndefinedMethod();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A {
   void myUndefinedMethod() {
   }
 }
 main(A a) {
   a.myUndefinedMethod();
 }
 ''');
   }
 
-  void test_undefinedMethod_createQualified_targetIsFunctionType() {
+  test_undefinedMethod_createQualified_targetIsFunctionType() async {
     resolveTestUnit('''
 typedef A();
 main() {
   A.myUndefinedMethod();
 }
 ''');
-    assertNoFix(DartFixKind.CREATE_METHOD);
+    await assertNoFix(DartFixKind.CREATE_METHOD);
   }
 
-  void test_undefinedMethod_createQualified_targetIsUnresolved() {
+  test_undefinedMethod_createQualified_targetIsUnresolved() async {
     resolveTestUnit('''
 main() {
   NoSuchClass.myUndefinedMethod();
 }
 ''');
-    assertNoFix(DartFixKind.CREATE_METHOD);
+    await assertNoFix(DartFixKind.CREATE_METHOD);
   }
 
-  void test_undefinedMethod_createUnqualified_parameters() {
+  test_undefinedMethod_createUnqualified_parameters() async {
     resolveTestUnit('''
 class A {
   main() {
     myUndefinedMethod(0, 1.0, '3');
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A {
   main() {
     myUndefinedMethod(0, 1.0, '3');
   }
 
   void myUndefinedMethod(int i, double d, String s) {
   }
 }
@@ skipping 17 matching lines @@
             ['double', 'num', 'Object', 'Comparable']));
     _assertLinkedGroup(change.linkedEditGroups[index++], ['d,']);
     _assertLinkedGroup(
         change.linkedEditGroups[index++],
         ['String s'],
         expectedSuggestions(
             LinkedEditSuggestionKind.TYPE, ['String', 'Object', 'Comparable']));
     _assertLinkedGroup(change.linkedEditGroups[index++], ['s)']);
   }
 
-  void test_undefinedMethod_createUnqualified_returnType() {
+  test_undefinedMethod_createUnqualified_returnType() async {
     resolveTestUnit('''
 class A {
   main() {
     int v = myUndefinedMethod();
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A {
   main() {
     int v = myUndefinedMethod();
   }
 
   int myUndefinedMethod() {
   }
 }
 ''');
     // linked positions
     _assertLinkedGroup(change.linkedEditGroups[0], ['int myUndefinedMethod(']);
     _assertLinkedGroup(change.linkedEditGroups[1],
         ['myUndefinedMethod();', 'myUndefinedMethod() {']);
   }
 
-  void test_undefinedMethod_createUnqualified_staticFromField() {
+  test_undefinedMethod_createUnqualified_staticFromField() async {
     resolveTestUnit('''
 class A {
   static var f = myUndefinedMethod();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A {
   static var f = myUndefinedMethod();
 
   static myUndefinedMethod() {
   }
 }
 ''');
   }
 
-  void test_undefinedMethod_createUnqualified_staticFromMethod() {
+  test_undefinedMethod_createUnqualified_staticFromMethod() async {
     resolveTestUnit('''
 class A {
   static main() {
     myUndefinedMethod();
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A {
   static main() {
     myUndefinedMethod();
   }
 
   static void myUndefinedMethod() {
   }
 }
 ''');
   }
 
-  void test_undefinedMethod_hint_createQualified_fromInstance() {
+  test_undefinedMethod_hint_createQualified_fromInstance() async {
     resolveTestUnit('''
 class A {
 }
 main() {
   var a = new A();
   a.myUndefinedMethod();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CREATE_METHOD,
         '''
 class A {
   void myUndefinedMethod() {
   }
 }
 main() {
   var a = new A();
   a.myUndefinedMethod();
 }
 ''');
   }
 
-  void test_undefinedMethod_parameterType_differentPrefixInTargetUnit() {
+  test_undefinedMethod_parameterType_differentPrefixInTargetUnit() async {
     String code2 = r'''
 library test2;
 import 'test3.dart' as bbb;
 export 'test3.dart';
 class D {
 }
 ''';
     addSource('/test2.dart', code2);
     addSource(
         '/test3.dart',
         r'''
 library test3;
 class E {}
 ''');
     resolveTestUnit('''
 library test;
 import 'test2.dart' as aaa;
 main(aaa.D d, aaa.E e) {
   d.foo(e);
 }
 ''');
     AnalysisError error = _findErrorToFix();
-    fix = _assertHasFix(DartFixKind.CREATE_METHOD, error);
+    fix = await _assertHasFix(DartFixKind.CREATE_METHOD, error);
     change = fix.change;
     // apply to "test2.dart"
     List<SourceFileEdit> fileEdits = change.edits;
     expect(fileEdits, hasLength(1));
     SourceFileEdit fileEdit = change.edits[0];
     expect(fileEdit.file, '/test2.dart');
     expect(
         SourceEdit.applySequence(code2, fileEdit.edits),
         r'''
 library test2;
 import 'test3.dart' as bbb;
 export 'test3.dart';
 class D {
   void foo(bbb.E e) {
   }
 }
 ''');
   }
 
-  void test_undefinedMethod_parameterType_inTargetUnit() {
+  test_undefinedMethod_parameterType_inTargetUnit() async {
     String code2 = r'''
 library test2;
 class D {
 }
 class E {}
 ''';
     addSource('/test2.dart', code2);
     resolveTestUnit('''
 library test;
 import 'test2.dart' as test2;
 main(test2.D d, test2.E e) {
   d.foo(e);
 }
 ''');
     AnalysisError error = _findErrorToFix();
-    fix = _assertHasFix(DartFixKind.CREATE_METHOD, error);
+    fix = await _assertHasFix(DartFixKind.CREATE_METHOD, error);
     change = fix.change;
     // apply to "test2.dart"
     List<SourceFileEdit> fileEdits = change.edits;
     expect(fileEdits, hasLength(1));
     SourceFileEdit fileEdit = change.edits[0];
     expect(fileEdit.file, '/test2.dart');
     expect(
         SourceEdit.applySequence(code2, fileEdit.edits),
         r'''
 library test2;
 class D {
   void foo(E e) {
   }
 }
 class E {}
 ''');
   }
 
-  void test_undefinedMethod_useSimilar_ignoreOperators() {
+  test_undefinedMethod_useSimilar_ignoreOperators() async {
     resolveTestUnit('''
 main(Object object) {
   object.then();
 }
 ''');
-    assertNoFix(DartFixKind.CHANGE_TO);
+    await assertNoFix(DartFixKind.CHANGE_TO);
   }
 
-  void test_undefinedMethod_useSimilar_qualified() {
+  test_undefinedMethod_useSimilar_qualified() async {
     resolveTestUnit('''
 class A {
   myMethod() {}
 }
 main() {
   A a = new A();
   a.myMehtod();
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 class A {
   myMethod() {}
 }
 main() {
   A a = new A();
   a.myMethod();
 }
 ''');
   }
 
-  void test_undefinedMethod_useSimilar_unqualified_superClass() {
+  test_undefinedMethod_useSimilar_unqualified_superClass() async {
     resolveTestUnit('''
 class A {
   myMethod() {}
 }
 class B extends A {
   main() {
     myMehtod();
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 class A {
   myMethod() {}
 }
 class B extends A {
   main() {
     myMethod();
   }
 }
 ''');
   }
 
-  void test_undefinedMethod_useSimilar_unqualified_thisClass() {
+  test_undefinedMethod_useSimilar_unqualified_thisClass() async {
     resolveTestUnit('''
 class A {
   myMethod() {}
   main() {
     myMehtod();
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 class A {
   myMethod() {}
   main() {
     myMethod();
   }
 }
 ''');
   }
 
-  void test_undefinedSetter_useSimilar_hint() {
+  test_undefinedSetter_useSimilar_hint() async {
     resolveTestUnit('''
 class A {
   int myField;
 }
 main(A a) {
   var x = a;
   x.myFild = 42;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 class A {
   int myField;
 }
 main(A a) {
   var x = a;
   x.myField = 42;
 }
 ''');
   }
 
-  void test_undefinedSetter_useSimilar_qualified() {
+  test_undefinedSetter_useSimilar_qualified() async {
     resolveTestUnit('''
 class A {
   int myField;
 }
 main(A a) {
   a.myFild = 42;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 class A {
   int myField;
 }
 main(A a) {
   a.myField = 42;
 }
 ''');
   }
 
-  void test_undefinedSetter_useSimilar_unqualified() {
+  test_undefinedSetter_useSimilar_unqualified() async {
     resolveTestUnit('''
 class A {
   int myField;
   main() {
     myFild = 42;
   }
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.CHANGE_TO,
         '''
 class A {
   int myField;
   main() {
     myField = 42;
   }
 }
 ''');
   }
 
-  void test_useEffectiveIntegerDivision() {
+  test_useEffectiveIntegerDivision() async {
     resolveTestUnit('''
 main() {
   var a = 5;
   var b = 2;
   print((a / b).toInt());
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.USE_EFFECTIVE_INTEGER_DIVISION,
         '''
 main() {
   var a = 5;
   var b = 2;
   print(a ~/ b);
 }
 ''');
   }
 
-  void test_useImportPrefix_withClass() {
+  test_useImportPrefix_withClass() async {
     resolveTestUnit('''
 import 'dart:async' as pref;
 main() {
   pref.Stream s = null;
   Future f = null;
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_PREFIX,
         '''
 import 'dart:async' as pref;
 main() {
   pref.Stream s = null;
   pref.Future f = null;
 }
 ''');
   }
 
-  void test_useImportPrefix_withTopLevelVariable() {
+  test_useImportPrefix_withTopLevelVariable() async {
     resolveTestUnit('''
 import 'dart:math' as pref;
 main() {
   print(pref.E);
   print(PI);
 }
 ''');
-    assertHasFix(
+    await assertHasFix(
         DartFixKind.IMPORT_LIBRARY_PREFIX,
         '''
 import 'dart:math' as pref;
 main() {
   print(pref.E);
   print(pref.PI);
 }
 ''');
   }
 
   /**
    * Computes fixes and verifies that there is a fix of the given kind.
    */
-  Fix _assertHasFix(FixKind kind, AnalysisError error) {
-    List<Fix> fixes = _computeFixes(error);
+  Future<Fix> _assertHasFix(FixKind kind, AnalysisError error) async {
+    List<Fix> fixes = await _computeFixes(error);
     for (Fix fix in fixes) {
       if (fix.kind == kind) {
         return fix;
       }
     }
     throw fail('Expected to find fix $kind in\n${fixes.join('\n')}');
   }
 
   void _assertLinkedGroup(LinkedEditGroup group, List<String> expectedStrings,
       [List<LinkedEditSuggestion> expectedSuggestions]) {
     List<Position> expectedPositions = _findResultPositions(expectedStrings);
     expect(group.positions, unorderedEquals(expectedPositions));
     if (expectedSuggestions != null) {
       expect(group.suggestions, unorderedEquals(expectedSuggestions));
     }
   }
 
   /**
    * Computes fixes for the given [error] in [testUnit].
    */
-  List<Fix> _computeFixes(AnalysisError error) {
-    FixProcessor processor = new FixProcessor(provider, testUnit, error);
+  Future<List<Fix>> _computeFixes(AnalysisError error) async {
+    DartFixContext dartContext = new DartFixContextImpl(
+        new FixContextImpl(provider, context, error), testUnit);
+    FixProcessor processor = new FixProcessor(dartContext);
     return processor.compute();
   }
 
   /**
    * Configures the [SourceFactory] to have the `my_pkg` package in
    * `/packages/my_pkg/lib` folder.
    */
   void _configureMyPkg(String myLibCode) {
     provider.newFile('/packages/my_pkg/lib/my_lib.dart', myLibCode);
     // configure SourceFactory
@@ skipping 22 matching lines @@
       int offset = resultCode.indexOf(search);
       positions.add(new Position(testFile, offset));
     }
     return positions;
   }
 
   void _performAnalysis() {
     while (context.performAnalysisTask().hasMoreWork);
   }
 }