Split AssetGraph.results into two streams.

pkg/barback/test/asset_graph/errors_test.dart

 // Copyright (c) 2013, 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 barback.test.asset_graph.source_test;
 
 import 'dart:async';
 
 import 'package:barback/barback.dart';
 import 'package:barback/src/asset_graph.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../utils.dart';
 
 main() {
   initConfig();
 
   test("errors if two transformers output the same file", () {
     initGraph(["app|foo.a"], [
       [
         new RewriteTransformer("a", "b"),
         new RewriteTransformer("a", "b")
       ]
     ]);
     updateSources(["app|foo.a"]);
 
-    expectCollision("app|foo.b");
+    buildShouldFail([isAssetCollisionException("app|foo.b")]);
   });
 
   test("does not report asset not found errors in results", () {
     initGraph();
 
     expectNoAsset("app|foo.txt");
     buildShouldSucceed();
   });
 
   test("reports an error for an unprovided source", () {
     initGraph();
     updateSources(["app|unknown.txt"]);
 
-    buildShouldFail((error) {
-      expect(error, new isInstanceOf<AssetNotFoundException>());
-      expect(error.id, equals(new AssetId.parse("app|unknown.txt")));
-    });
+    buildShouldFail([isAssetNotFoundException("app|unknown.txt")]);
   });
 
   test("reports missing input errors in results", () {
     initGraph({"app|a.txt": "a.inc"}, [
       [new ManyToOneTransformer("txt")]
     ]);
 
-    buildShouldFail((error) {
-      expect(error, new isInstanceOf<MissingInputException>());
-      expect(error.id, equals(new AssetId.parse("app|a.inc")));
-    });
+    buildShouldFail([isMissingInputException("app|a.inc")]);
 
     updateSources(["app|a.txt"]);
 
     expectNoAsset("app|a.out");
   });
 
   test("fails if a non-primary input is removed", () {
     initGraph({
       "app|a.txt": "a.inc,b.inc,c.inc",
       "app|a.inc": "a",
       "app|b.inc": "b",
       "app|c.inc": "c"
     }, [
       [new ManyToOneTransformer("txt")]
     ]);
 
     updateSources(["app|a.txt", "app|a.inc", "app|b.inc", "app|c.inc"]);
     expectAsset("app|a.out", "abc");
     buildShouldSucceed();
 
     schedule(() {
       removeSources(["app|b.inc"]);
     });
 
-    buildShouldFail((error) {
-      expect(error, new isInstanceOf<MissingInputException>());
-      expect(error.id, equals(new AssetId.parse("app|b.inc")));
-    });
+    buildShouldFail([isMissingInputException("app|b.inc")]);
     expectNoAsset("app|a.out");
   });
 
   test("catches transformer exceptions and reports them", () {
     initGraph(["app|foo.txt"], [
       [new BadTransformer(["app|foo.out"])]
     ]);
 
     schedule(() {
       updateSources(["app|foo.txt"]);
     });
 
     expectNoAsset("app|foo.out");
 
-    buildShouldFail((error) {
-      expect(error, equals(BadTransformer.ERROR));
-    });
+    buildShouldFail([equals(BadTransformer.ERROR)]);
   });
 
   // TODO(rnystrom): Is this the behavior we expect? If a transformer fails
   // to transform a file, should we just skip past it to the source?
   test("yields a source if a transform fails on it", () {
     initGraph(["app|foo.txt"], [
       [new BadTransformer(["app|foo.txt"])]
     ]);
 
     schedule(() {
       updateSources(["app|foo.txt"]);
     });
 
     expectAsset("app|foo.txt");
   });
 
   test("catches errors even if nothing is waiting for process results", () {
     initGraph(["app|foo.txt"], [[new BadTransformer([])]]);
 
     schedule(() {
       updateSources(["app|foo.txt"]);
     });
 
     // Note: No asset requests here.
 
-    buildShouldFail((error) {
-      expect(error, equals(BadTransformer.ERROR));
-    });
+    buildShouldFail([equals(BadTransformer.ERROR)]);
   });
 
   test("discards outputs from failed transforms", () {
     initGraph(["app|foo.txt"], [
       [new BadTransformer(["a.out", "b.out"])]
     ]);
 
     schedule(() {
       updateSources(["app|foo.txt"]);
     });
 
     expectNoAsset("app|a.out");
   });
 }