Create AST structure for asserts in constructor initializers

pkg/analyzer/test/generated/parser_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 analyzer.test.generated.parser_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/error/error.dart';
@@ skipping 7828 matching lines @@
 
   void test_parseConstructor_assert() {
     enableAssertInitializer = true;
     createParser('C(x, y) : _x = x, assert (x < y), _y = y;');
     ClassMember member = parser.parseClassMember('C');
     expectNotNullIfNoErrors(member);
     listener.assertNoErrors();
     expect(member, new isInstanceOf<ConstructorDeclaration>());
     ConstructorDeclaration constructor = member as ConstructorDeclaration;
     NodeList<ConstructorInitializer> initializers = constructor.initializers;
-    expect(initializers, hasLength(2));
+    expect(initializers, hasLength(3));
+    ConstructorInitializer initializer = initializers[1];
+    expect(initializer, new isInstanceOf<AssertInitializer>());
+    AssertInitializer assertInitializer = initializer;
+    expect(assertInitializer.condition, isNotNull);
+    expect(assertInitializer.message, isNull);
   }
 
   void test_parseConstructor_with_pseudo_function_literal() {
     // "(b) {}" should not be misinterpreted as a function literal even though
     // it looks like one.
     createParser('C() : a = (b) {}');
     ClassMember member = parser.parseClassMember('C');
     expectNotNullIfNoErrors(member);
     listener.assertNoErrors();
     expect(member, new isInstanceOf<ConstructorDeclaration>());
@@ skipping 5614 matching lines @@
   CompilationUnit _parseDirectives(String source,
       [List<ErrorCode> errorCodes = const <ErrorCode>[]]) {
     createParser(source);
     CompilationUnit unit = parser.parseDirectives2();
     expect(unit, isNotNull);
     expect(unit.declarations, hasLength(0));
     listener.assertErrorsWithCodes(errorCodes);
     return unit;
   }
 }