Fixes #179 -- compile error if editing files during server mode

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 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
-import 'package:analyzer/src/generated/engine.dart' show TimestampedData;
+import 'package:analyzer/src/generated/engine.dart'
+    show AnalysisContext, TimestampedData;
 import 'package:analyzer/src/generated/source.dart';
 import 'package:logging/logging.dart';
 import 'package:path/path.dart' as path;
 import 'package:source_span/source_span.dart';
 import 'package:unittest/unittest.dart';
 
 import 'package:dev_compiler/src/checker/dart_sdk.dart'
     show mockSdkSources, dartSdkDirectory;
 import 'package:dev_compiler/src/checker/resolver.dart' show TypeResolver;
 import 'package:dev_compiler/src/utils.dart';
@@ skipping 24 matching lines @@
 ///
 ///     testChecker({
 ///       '/main.dart': '''
 ///           testMethod() {
 ///             dynamic x = /*warning:Box*/3;
 ///           }
 ///       '''
 ///     });
 ///
 CheckerResults testChecker(Map<String, String> testFiles,
-    {bool allowConstCasts: true, String sdkDir, CheckerReporter reporter,
+    {bool allowConstCasts: true, String sdkDir,
+    CheckerReporter createReporter(AnalysisContext context),
     covariantGenerics: true, relaxedCasts: true,
     inferDownwards: RulesOptions.inferDownwardsDefault,
     inferFromOverrides: ResolverOptions.inferFromOverridesDefault,
     inferTransitively: ResolverOptions.inferTransitivelyDefault,
     nonnullableTypes: TypeOptions.NONNULLABLE_TYPES,
     wrapClosures: RulesOptions.wrapClosuresDefault}) {
   expect(testFiles.containsKey('/main.dart'), isTrue,
       reason: '`/main.dart` is missing in testFiles');
 
   // Create a resolver that can load test files from memory.
   var testUriResolver = new InMemoryUriResolver(testFiles);
   var options = new CompilerOptions(
       allowConstCasts: allowConstCasts,
       covariantGenerics: covariantGenerics,
       relaxedCasts: relaxedCasts,
       inferDownwards: inferDownwards,
       inferFromOverrides: inferFromOverrides,
       inferTransitively: inferTransitively,
       nonnullableTypes: nonnullableTypes,
       wrapClosures: wrapClosures,
       useMockSdk: sdkDir == null,
       dartSdkPath: sdkDir,
       runtimeDir: '/dev_compiler_runtime/',
       entryPointFile: '/main.dart');
   var resolver = sdkDir == null
       ? new TypeResolver.fromMock(mockSdkSources, options,
           otherResolvers: [testUriResolver])
       : new TypeResolver.fromDir(sdkDir, options,
           otherResolvers: [testUriResolver]);
+  var context = resolver.context;
 
   // Run the checker on /main.dart.
   var mainFile = new Uri.file('/main.dart');
-  var checkExpectations = reporter == null;
-  if (reporter == null) reporter = new TestReporter();
+  var checkExpectations = createReporter == null;
+  var reporter = (createReporter == null)
+      ? new TestReporter(context)
+      : createReporter(context);
   var results =
       new Compiler(options, resolver: resolver, reporter: reporter).run();
 
   // Extract expectations from the comments in the test files.
   var expectedErrors = <AstNode, List<_ErrorExpectation>>{};
   var visitor = new _ErrorMarkerVisitor(expectedErrors);
   var initialLibrary =
       resolver.context.getLibraryElement(testUriResolver.files[mainFile]);
   for (var lib in reachableLibraries(initialLibrary)) {
     for (var unit in lib.units) {
@@ skipping 41 matching lines @@
     }
   }
 
   return results;
 }
 
 class TestReporter extends SummaryReporter {
   Map<Uri, Map<AstNode, List<StaticInfo>>> infoMap = {};
   Uri _current;
 
+  TestReporter(AnalysisContext context) : super(context);
+
   void enterLibrary(Uri uri) {
     super.enterLibrary(uri);
     infoMap[uri] = {};
     _current = uri;
   }
 
   void log(Message info) {
     super.log(info);
     if (info is StaticInfo) {
       infoMap[_current].putIfAbsent(info.node, () => []).add(info);
@@ skipping 105 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 $type';
 }