fixes #6, refactor to use AnalysisError/Listener throughout dev_compiler

lib/src/testing.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dev_compiler.src.testing;
 
 import 'dart:collection' show Queue;
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/src/generated/ast.dart';
@@ skipping 160 matching lines @@
   }
 
   void _expectError(AstNode node, _ErrorExpectation expected) {
 
     // See if we can find the expected error in our actual errors
     for (var actual in _actualErrors) {
       if (actual.offset == node.offset && actual.length == node.length) {
         var actualMsg = _formatActualError(actual);
         expect(_actualErrorLevel(actual), expected.level,
             reason: 'expected different error code at:\n\n$actualMsg');
-        expect(actual.errorCode.name, expected.typeName,
+        expect(errorCodeName(actual.errorCode), expected.typeName,
             reason: 'expected different error type at:\n\n$actualMsg');
 
         // We found it. Stop the search.
         _actualErrors.remove(actual);
         return;
       }
     }
 
     var span = _createSpan(node.offset, node.length);
     var levelName = expected.level.name.toLowerCase();
     var msg = span.message(expected.typeName, color: colorOf(levelName));
     fail('expected error was not reported at:\n\n$levelName: $msg');
   }
 
   Level _actualErrorLevel(AnalysisError actual) {
     return const <ErrorSeverity, Level>{
       ErrorSeverity.ERROR: Level.SEVERE,
       ErrorSeverity.WARNING: Level.WARNING,
       ErrorSeverity.INFO: Level.INFO
     }[actual.errorCode.errorSeverity];
   }
 
   String _formatActualError(AnalysisError actual) {
     var span = _createSpan(actual.offset, actual.length);
     var levelName = _actualErrorLevel(actual).name.toLowerCase();
     var msg = span.message(actual.message, color: colorOf(levelName));
-    return '$levelName: [${actual.errorCode.name}] $msg';
+    return '$levelName: [${errorCodeName(actual.errorCode)}] $msg';
   }
 
   SourceSpan _createSpan(int offset, int len) {
     return createSpanHelper(
-        _unit, offset, offset + len, _unit.element.source, _unitSourceCode);
+        _unit.lineInfo, offset, offset + len, _unit.element.source, _unitSourceCode);
   }
 }
 
 /// Describes an expected message that should be produced by the checker.
 class _ErrorExpectation {
   final Level level;
   final String typeName;
   _ErrorExpectation(this.level, this.typeName);
 
   static _ErrorExpectation _parse(String descriptor) {
@@ skipping 19 matching lines @@
     expect(tokens[1], "should", reason: 'invalid error descriptor');
     expect(tokens[2], "be", reason: 'invalid error descriptor');
     if (tokens[0] == "pass") return null;
     // TODO(leafp) For now, we just use whatever the current expectation is,
     // eventually we could do more automated reporting here.
     return _parse(tokens[0]);
   }
 
   String toString() => '$level $typeName';
 }