Make barback more package-aware.

pkg/barback/test/utils.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.utils;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:io';
 
 import 'package:barback/barback.dart';
 import 'package:barback/src/asset_graph.dart';
+import 'package:barback/src/asset_graph_manager.dart';
+import 'package:barback/src/utils.dart';
 import 'package:pathos/path.dart' as pathos;
 import 'package:scheduled_test/scheduled_test.dart';
+import 'package:stack_trace/stack_trace.dart';
 
 // TODO(rnystrom): Get rid of this or find a better path for it.
 import '../../../sdk/lib/_internal/pub/test/command_line_config.dart';
 
 var _configured = false;
 
 MockProvider _provider;
-AssetGraph _graph;
+AssetGraphManager _graphManager;
 
 /// Calls to [buildShouldSucceed] and [buildShouldFail] set expectations on
 /// successive [BuildResult]s from [_graph]. This keeps track of how many calls
 /// have already been made so later calls know which result to look for.
 int _nextBuildResult;
 
 void initConfig() {
   if (_configured) return;
   _configured = true;
   unittestConfiguration = new CommandLineConfiguration();
 }
 
 /// Creates a new [AssetProvider] and [AssetGraph] with the given [assets] and
 /// [transformers].
 ///
 /// This graph is used internally by most of the other functions in this
 /// library so you must call it in the test before calling any of the other
 /// functions.
 ///
 /// [assets] may either be an [Iterable] or a [Map]. If it's an [Iterable],
 /// each element may either be an [AssetId] or a string that can be parsed to
 /// one. If it's a [Map], each key should be a string that can be parsed to an
 /// [AssetId] and the value should be a string defining the contents of that
 /// asset.
-void initGraph([assets, Iterable<Iterable<Transformer>> transformers]) {
+///
+/// [transformers] is a map from package names to the transformers for each
+/// package.
+void initGraph([assets,
+    Map<String, Iterable<Iterable<Transformer>>> transformers]) {
   if (assets == null) assets = [];
-  if (transformers == null) transformers = [];
+  if (transformers == null) transformers = {};
 
-  _provider = new MockProvider(assets);
-  _graph = new AssetGraph(_provider, transformers);
+  _provider = new MockProvider(assets, transformers);
+  _graphManager = new AssetGraphManager(_provider);
   _nextBuildResult = 0;
 }
 
 /// Updates [assets] in the current [AssetProvider].
 ///
 /// Each item in the list may either be an [AssetId] or a string that can be
 /// parsed as one. Note that this method is not automatically scheduled.
 void updateSources(Iterable assets) {
   // Allow strings as asset IDs.
   assets = assets.map((asset) {
     if (asset is String) return new AssetId.parse(asset);
     return asset;
   });
 
-  _graph.updateSources(assets);
+  _graphManager.updateSources(assets);
 }
 
 /// Removes [assets] from the current [AssetProvider].
 ///
 /// Each item in the list may either be an [AssetId] or a string that can be
 /// parsed as one. Note that this method is not automatically scheduled.
 void removeSources(Iterable assets) {
   // Allow strings as asset IDs.
   assets = assets.map((asset) {
     if (asset is String) return new AssetId.parse(asset);
     return asset;
   });
 
-  _graph.removeSources(assets);
+  _graphManager.removeSources(assets);
 }
 
 /// Schedules a change to the contents of an asset identified by [name] to
 /// [contents].
 ///
 /// Does not update it in the graph.
 void modifyAsset(String name, String contents) {
   schedule(() {
     _provider._modifyAsset(name, contents);
   }, "modify asset $name");
 }
 
 /// Schedules a pause of the internally created [AssetProvider].
 ///
 /// All asset requests that the [AssetGraph] makes to the provider after this
 /// will not complete until [resumeProvider] is called.
 void pauseProvider() {
-  schedule(() =>_provider._pause(), "pause provider");
+  schedule(() => _provider._pause(), "pause provider");
 }
 
 /// Schedules an unpause of the provider after a call to [pauseProvider] and
 /// allows all pending asset loads to finish.
 void resumeProvider() {
   schedule(() => _provider._resume(), "resume provider");
 }
 
+/// Asserts that the current build step shouldn't have finished by this point in
+/// the schedule.
+///
+/// This uses the same build counter as [buildShouldSucceed] and
+/// [buildShouldFail], so those can be used to validate build results before and
+/// after this.
+void buildShouldNotBeDone() {
+  var resultAllowed = false;
+  var trace = new Trace.current();
+  _graphManager.results.elementAt(_nextBuildResult).then((result) {
+    if (resultAllowed) return;
+
+    currentSchedule.signalError(
+        new Exception("Expected build not to terminate "
+            "here, but it terminated with result: $result"), trace);
+  }).catchError((error) {
+    if (resultAllowed) return;
+    currentSchedule.signalError(error);
+  });
+
+  schedule(() {
+    // Pump the event queue in case the build completes out-of-band after we get
+    // here. If it does, we want to signal an error.
+    return pumpEventQueue().then((_) {
+      resultAllowed = true;
+    });
+  }, "ensuring build doesn't terminate");
+}
+
 /// Expects that the next [BuildResult] is a build success.
 void buildShouldSucceed() {
-  expect(_graph.results.elementAt(_nextBuildResult++).then((result) {
+  expect(_getNextBuildResult().then((result) {
     expect(result.succeeded, isTrue);
   }), completes);
 }
 
 /// Expects that the next [BuildResult] emitted is a failure.
 ///
 /// [matchers] is a list of matchers to match against the errors that caused the
 /// build to fail. Every matcher is expected to match an error, but the order of
 /// matchers is unimportant.
 void buildShouldFail(List matchers) {
-  expect(_graph.results.elementAt(_nextBuildResult++).then((result) {
+  expect(_getNextBuildResult().then((result) {
     expect(result.succeeded, isFalse);
     expect(result.errors.length, equals(matchers.length));
     for (var matcher in matchers) {
       expect(result.errors, contains(matcher));
     }
   }), completes);
 }
 
+Future<BuildResult> _getNextBuildResult() =>
+  _graphManager.results.elementAt(_nextBuildResult++);
+
 /// Pauses the schedule until the currently running build completes.
 ///
 /// Validates that the build completed successfully.
 void waitForBuild() {
   schedule(() {
-    return _graph.results.first.then((result) {
+    return _graphManager.results.first.then((result) {
       expect(result.succeeded, isTrue);
     });
   }, "wait for build");
 }
 
 /// Schedules an expectation that the graph will deliver an asset matching
 /// [name] and [contents].
 ///
 /// If [contents] is omitted, defaults to the asset's filename without an
 /// extension (which is the same default that [initGraph] uses).
 void expectAsset(String name, [String contents]) {
   var id = new AssetId.parse(name);
 
   if (contents == null) {
     contents = pathos.basenameWithoutExtension(id.path);
   }
 
   schedule(() {
-    return _graph.getAssetById(id).then((asset) {
+    return _graphManager.getAssetById(id).then((asset) {
       // TODO(rnystrom): Make an actual Matcher class for this.
       expect(asset, new isInstanceOf<MockAsset>());
       expect(asset.id, equals(id));
       expect(asset.contents, equals(contents));
     });
   }, "get asset $name");
 }
 
 /// Schedules an expectation that the graph will not find an asset matching
 /// [name].
 void expectNoAsset(String name) {
   var id = new AssetId.parse(name);
 
   // Make sure the future gets the error.
   schedule(() {
-    return _graph.getAssetById(id).then((asset) {
+    return _graphManager.getAssetById(id).then((asset) {
       fail("Should have thrown error but got $asset.");
     }).catchError((error) {
       expect(error, new isInstanceOf<AssetNotFoundException>());
       expect(error.id, equals(id));
     });
   }, "get asset $name");
 }
 
-/// Schedules an expectation that [graph] will have an error on an asset
-/// matching [name] for missing [input].
-Future expectMissingInput(AssetGraph graph, String name, String input) {
-  var missing = new AssetId.parse(input);
-
-  // Make sure the future gets the error.
-  schedule(() {
-    return graph.getAssetById(new AssetId.parse(name)).then((asset) {
-      fail("Should have thrown error but got $asset.");
-    }).catchError((error) {
-      expect(error, new isInstanceOf<MissingInputException>());
-      expect(error.id, equals(missing));
-    });
-  }, "get missing input on $name");
-}
-
 /// Returns a matcher for an [AssetNotFoundException] with the given [id].
 Matcher isAssetNotFoundException(String name) {
   var id = new AssetId.parse(name);
   return allOf(
       new isInstanceOf<AssetNotFoundException>(),
       predicate((error) => error.id == id, 'id is $name'));
 }
 
 /// Returns a matcher for an [AssetCollisionException] with the given [id].
 Matcher isAssetCollisionException(String name) {
   var id = new AssetId.parse(name);
   return allOf(
       new isInstanceOf<AssetCollisionException>(),
       predicate((error) => error.id == id, 'id is $name'));
 }
 
 /// Returns a matcher for a [MissingInputException] with the given [id].
 Matcher isMissingInputException(String name) {
   var id = new AssetId.parse(name);
   return allOf(
       new isInstanceOf<MissingInputException>(),
       predicate((error) => error.id == id, 'id is $name'));
 }
 
+/// Returns a matcher for an [InvalidOutputException] with the given id and
+/// package name.
+Matcher isInvalidOutputException(String package, String name) {
+  var id = new AssetId.parse(name);
+  return allOf(
+      new isInstanceOf<InvalidOutputException>(),
+      predicate((error) => error.package == package, 'package is $package'),
+      predicate((error) => error.id == id, 'id is $name'));
+}
+
 /// An [AssetProvider] that provides the given set of assets.
 class MockProvider implements AssetProvider {
   Iterable<String> get packages => _packages.keys;
 
-  final _packages = new Map<String, List<MockAsset>>();
+  Map<String, _MockPackage> _packages;
 
   /// The completer that [getAsset()] is waiting on to complete when paused.
   ///
   /// If `null` it will return the asset immediately.
   Completer _pauseCompleter;
 
   /// Tells the provider to wait during [getAsset] until [complete()]
   /// is called.
   ///
   /// Lets you test the asynchronous behavior of loading.
   void _pause() {
     _pauseCompleter = new Completer();
   }
 
   void _resume() {
     _pauseCompleter.complete();
     _pauseCompleter = null;
   }
 
-  MockProvider(assets) {
+  MockProvider(assets,
+      Map<String, Iterable<Iterable<Transformer>>> transformers) {
+    var assetList;
     if (assets is Map) {
-      assets.forEach((asset, contents) {
+      assetList = assets.keys.map((asset) {
         var id = new AssetId.parse(asset);
-        var package = _packages.putIfAbsent(id.package, () => []);
-        package.add(new MockAsset(id, contents));
+        return new MockAsset(id, assets[asset]);
       });
     } else if (assets is Iterable) {
-      for (var asset in assets) {
+      assetList = assets.map((asset) {
         var id = new AssetId.parse(asset);
-        var package = _packages.putIfAbsent(id.package, () => []);
         var contents = pathos.basenameWithoutExtension(id.path);
-        package.add(new MockAsset(id, contents));
-      }
+        return new MockAsset(id, contents);
+      });
     }
+
+    _packages = mapMapValues(groupBy(assetList, (asset) => asset.id.package),
+        (package, assets) {
+      var packageTransformers = transformers[package];
+      if (packageTransformers == null) packageTransformers = [];
+      return new _MockPackage(assets, packageTransformers.toList());
+    });
+
+    // If there are no assets or transformers, add a dummy package. This better
+    // simulates the real world, where there'll always be at least the
+    // entrypoint package.
+    if (_packages.isEmpty) _packages = {"app": new _MockPackage([], [])};
   }
 
   void _modifyAsset(String name, String contents) {
     var id = new AssetId.parse(name);
-    var asset = _packages[id.package].firstWhere((a) => a.id == id);
+    var asset = _packages[id.package].assets.firstWhere((a) => a.id == id);
     asset.contents = contents;
   }
 
   List<AssetId> listAssets(String package, {String within}) {
     if (within != null) {
       throw new UnimplementedError("Doesn't handle 'within' yet.");
     }
 
-    return _packages[package].map((asset) => asset.id);
+    return _packages[package].assets.map((asset) => asset.id);
+  }
+
+  Iterable<Iterable<Transformer>> getTransformers(String package) {
+    var mockPackage = _packages[package];
+    if (mockPackage == null) {
+      throw new ArgumentError("No package named $package.");
+    }
+    return mockPackage.transformers;
   }
 
   Future<Asset> getAsset(AssetId id) {
     var future;
     if (_pauseCompleter != null) {
       future = _pauseCompleter.future;
     } else {
       future = new Future.value();
     }
 
     return future.then((_) {
       var package = _packages[id.package];
       if (package == null) throw new AssetNotFoundException(id);
 
-      return package.firstWhere((asset) => asset.id == id,
+      return package.assets.firstWhere((asset) => asset.id == id,
           orElse: () => throw new AssetNotFoundException(id));
     });
   }
 }
 
+/// Used by [MockProvider] to keep track of which assets and transformers exist
+/// for each package.
+class _MockPackage {
+  final List<MockAsset> assets;
+  final List<List<Transformer>> transformers;
+
+  _MockPackage(this.assets, Iterable<Iterable<Transformer>> transformers)
+      : transformers = transformers.map((phase) => phase.toList()).toList();
+}
+
 /// A [Transformer] that takes assets ending with one extension and generates
 /// assets with a given extension.
 ///
 /// Appends the output extension to the contents of the input file.
 class RewriteTransformer extends Transformer {
   final String from;
   final String to;
 
   /// The number of times the transformer has been applied.
   int numRuns = 0;
@@ skipping 159 matching lines @@
         var id = new AssetId.parse(output);
         transform.addOutput(new MockAsset(id, output));
       }
 
       // Then fail.
       throw ERROR;
     });
   }
 }
 
+/// A transformer that outputs an asset with the given id.
+class CreateAssetTransformer extends Transformer {
+  final String output;
+
+  CreateAssetTransformer(this.output);
+
+  Future<bool> isPrimary(Asset asset) => new Future.value(true);
+
+  Future apply(Transform transform) {
+    return new Future(() {
+      transform.addOutput(new MockAsset(new AssetId.parse(output), output));
+    });
+  }
+}
+
 /// An implementation of [Asset] that never hits the file system.
 class MockAsset implements Asset {
   final AssetId id;
   String contents;
 
   MockAsset(this.id, this.contents);
 
   Future<String> readAsString({Encoding encoding}) =>
       new Future.value(contents);
 
   Stream<List<int>> read() => throw new UnimplementedError();
 
   String toString() => "MockAsset $id $contents";
 }