Incremental compiler detects when library graph changes.

dart/tests/try/web/incremental_compilation_update_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 trydart.incremental_compilation_update_test;
 
 import 'dart:html' hide
     Element;
 
 import 'dart:async' show
@@ skipping 22 matching lines @@
 import '../poi/compiler_test_case.dart' show
     CompilerTestCase;
 
 import 'package:compiler/src/elements/elements.dart' show
     Element,
     LibraryElement;
 
 import 'package:compiler/src/dart2jslib.dart' show
     Compiler;
 
+import 'package:dart2js_incremental/dart2js_incremental.dart' show
+    IncrementalCompilationFailed;
+
 import 'program_result.dart';
 
 const int TIMEOUT = 100;
 
 const List<EncodedResult> tests = const <EncodedResult>[
     // Basic hello-world test.
     const EncodedResult(
         const [
             "main() { print('Hello, ",
             const ["", "Brave New "],
@@ skipping 1694 matching lines @@
           listener.expect(program.messagesWith('iframe-dart-main-done'));
       return future.then((_) {
         int version = 2;
         return Future.forEach(programs.skip(1), (ProgramResult program) {
 
           status.append(new HeadingElement.h2()..appendText("Update:"));
           status.append(numberedLines(program.code));
 
           WebInputProvider inputProvider =
               test.incrementalCompiler.inputProvider;
-          Uri uri = test.scriptUri.resolve('?v${version++}');
-          inputProvider.cachedSources[uri] = new Future.value(program.code);
+          Uri base = test.scriptUri;
+          Map<String, String> code = program.code is String
+              ? { 'main.dart': program.code }
+              : program.code;
+          Map<Uri, Uri> uriMap = <Uri, Uri>{};
+          for (String name in code.keys) {
+            Uri uri = base.resolve('$name?v${version++}');
+            inputProvider.cachedSources[uri] = new Future.value(code[name]);
+            uriMap[base.resolve(name)] = uri;
+          }
           Future future = test.incrementalCompiler.compileUpdates(
-              {test.scriptUri: uri}, logVerbose: logger, logTime: logger);
+              uriMap, logVerbose: logger, logTime: logger);
           future = future.catchError((error, trace) {
             String statusMessage;
             Future result;
-            if (program.compileUpdatesShouldThrow) {
+            if (program.compileUpdatesShouldThrow &&
+                error is IncrementalCompilationFailed) {
               statusMessage = "Expected error in compileUpdates.";
               result = null;
             } else {
               statusMessage = "Unexpected error in compileUpdates.";
               result = new Future.error(error, trace);
             }
             status.append(new HeadingElement.h3()..appendText(statusMessage));
             return result;
           });
           return future.then((String update) {
@@ skipping 121 matching lines @@
   position: absolute;
   left: 0px;
   width: 3em;
   text-align: right;
   background-color: lightgoldenrodyellow;
 }
 ''');
   style.type = 'text/css';
   return style;
 }