Support default constructors in analyzer2dart.

pkg/analyzer2dart/test/sexpr_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.
 
 /// Unittest test of the CPS ir generated by the analyzer2dart compiler.
 
 import 'mock_sdk.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source.dart';
+import 'package:compiler/src/cps_ir/cps_ir_nodes.dart';
 import 'package:compiler/src/cps_ir/cps_ir_nodes_sexpr.dart';
 import 'package:compiler/src/elements/elements.dart' as dart2js;
 import 'package:unittest/unittest.dart';
 
 import '../lib/src/closed_world.dart';
 import '../lib/src/driver.dart';
 import '../lib/src/converted_world.dart';
 import 'output_helper.dart';
 import 'test_helper.dart';
 import 'sexpr_data.dart';
 
-main() {
-  performTests(TEST_DATA, unittester, checkResult);
+main(List<String> args) {
+  performTests(TEST_DATA, unittester, checkResult, args);
 }
 
 checkResult(TestSpec result) {
   if (result.skipInAnalyzerFrontend) return;
   String input = result.input.trim();
   CollectingOutputProvider outputProvider = new CollectingOutputProvider();
   MemoryResourceProvider provider = new MemoryResourceProvider();
   DartSdk sdk = new MockSdk();
   Driver driver = new Driver(provider, sdk, outputProvider);
   String rootFile = '/root.dart';
   provider.newFile(rootFile, input);
   Source rootSource = driver.setRoot(rootFile);
   FunctionElement entryPoint = driver.resolveEntryPoint(rootSource);
   ClosedWorld world = driver.computeWorld(entryPoint);
   ConvertedWorld convertedWorld = convertWorld(world);
 
   void checkOutput(String elementName,
                    dart2js.Element element,
                    String expectedOutput) {
-    expectedOutput = expectedOutput.trim();
-    String output = convertedWorld.getIr(element)
-        .accept(new SExpressionStringifier());
-    expect(output, equals(expectedOutput),
-        reason: "\nInput:\n${result.input}\n"
-                "Expected for '$elementName':\n$expectedOutput\n"
-                "Actual for '$elementName':\n$output\n");
+    ExecutableDefinition ir = convertedWorld.getIr(element);
+    if (expectedOutput == null) {
+      expect(ir, isNull,
+          reason: "\nInput:\n${result.input}\n"
+                  "No CPS IR expected for $element");
+    } else {
+      expect(ir, isNotNull,
+          reason: "\nInput:\n${result.input}\n"
+                  "No CPS IR for $element");
+      expectedOutput = expectedOutput.trim();
+      String output = ir.accept(new SExpressionStringifier());
+      expect(output, equals(expectedOutput),
+          reason: "\nInput:\n${result.input}\n"
+                  "Expected for '$elementName':\n$expectedOutput\n"
+                  "Actual for '$elementName':\n$output\n");
+    }
   }
 
   if (result.output is String) {
     checkOutput('main', convertedWorld.mainFunction, result.output);
   } else {
     assert(result.output is Map<String, String>);
     dart2js.LibraryElement mainLibrary = convertedWorld.mainFunction.library;
     result.output.forEach((String elementName, String output) {
       bool found = false;
       List<String> names = <String>[];
       convertedWorld.resolvedElements.forEach((dart2js.Element element) {
         if (element.library == mainLibrary) {
           String name = element.name;
           if (element.enclosingClass != null) {
             name = '${element.enclosingClass.name}.$name';
           }
           if (name == elementName) {
             checkOutput(elementName, element, output);
             found = true;
           }
           names.add(name);
         }
       });
       expect(found, isTrue, reason: "'$elementName' not found in $names.");
     });
   }
 }