First pass at build dependency graph for barback.

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 'package:barback/barback.dart';
+import 'package:barback/src/asset_graph.dart';
+import 'package:pathos/path.dart' as pathos;
+import 'package:scheduled_test/scheduled_test.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;
+
+void initConfig() {
+  if (_configured) return;
+  _configured = true;
+  unittestConfiguration = new CommandLineConfiguration();
+}
+
+/// Expects that [graph] will return an asset matching [name] and [contents].
+void expectAsset(AssetGraph graph, 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) {
+      // TODO(rnystrom): Make an actual Matcher class for this.
+      expect(asset, new isInstanceOf<MockAsset>());
+      expect(asset._id.package, equals(id.package));
+      expect(asset._id.path, equals(id.path));
+      expect(asset._contents, equals(contents));
+    });
+  }, "get asset $name");
+}
+
+/// Expects that [graph] will not find an asset matching [name].
+void expectNoAsset(AssetGraph graph, String name) {
+  var id = new AssetId.parse(name);
+
+  // Make sure the future gets the error.
+  schedule(() {
+    return graph.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");
+}
+
+/// Expects that [graph] will have an output file collision error on an asset
+/// matching [name].
+Future expectCollision(AssetGraph graph, String name) {
+  var id = new AssetId.parse(name);
+  return schedule(() {
+    return graph.results.first.then((result) {
+      expect(result.error, new isInstanceOf<AssetCollisionException>());
+      expect(result.error.id, equals(id));
+    });
+  }, "get collision on $name");
+}
+
+/// Expects 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");
+}
+
+/// 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>>();
+
+  /// The completer that [getAsset()] is waiting on to complete.
+  ///
+  /// If `null` it will return the asset immediately.
+  Completer _wait;
+
+  /// Tells the provider to wait during [getAsset] until [complete()]
+  /// is called.
+  ///
+  /// Lets you test the asynchronous behavior of loading.
+  void wait() {
+    _wait = new Completer();
+  }
+
+  void complete() {
+    _wait.complete();
+    _wait = null;
+  }
+
+  MockProvider(assets) {
+    if (assets is Map) {
+      assets.forEach((asset, contents) {
+        var id = new AssetId.parse(asset);
+        var package = _packages.putIfAbsent(id.package, () => []);
+        package.add(new MockAsset(id, contents));
+      });
+    } else if (assets is Iterable) {
+      for (var asset in assets) {
+        var id = new AssetId.parse(asset);
+        var package = _packages.putIfAbsent(id.package, () => []);
+        var contents = pathos.basenameWithoutExtension(id.path);
+        package.add(new MockAsset(id, contents));
+      }
+    }
+  }
+
+  void modifyAsset(String name, String contents) {
+    var id = new AssetId.parse(name);
+    var asset = _packages[id.package].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);
+  }
+
+  Future<Asset> getAsset(AssetId id) {
+    var future;
+    if (_wait != null) {
+      future = _wait.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,
+          orElse: () => throw new AssetNotFoundException(id));
+    });
+  }
+}
+
+/// 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;
+
+  /// The number of currently running transforms.
+  int _runningTransforms = 0;
+
+  /// The completer that the transform is waiting on to complete.
+  ///
+  /// If `null` the transform will complete immediately.
+  Completer _wait;
+
+  /// A future that completes when the first apply of this transformer begins.
+  Future get started => _started.future;
+  final _started = new Completer();
+
+  /// Creates a transformer that rewrites assets whose extension is [from] to
+  /// one whose extension is [to].
+  ///
+  /// [to] may be a space-separated list in which case multiple outputs will be
+  /// created for each input.
+  RewriteTransformer(this.from, this.to);
+
+  /// `true` if any transforms are currently running.
+  bool get isRunning => _runningTransforms > 0;
+
+  /// Tells the transform to wait during its transformation until [complete()]
+  /// is called.
+  ///
+  /// Lets you test the asynchronous behavior of transformers.
+  void wait() {
+    _wait = new Completer();
+  }
+
+  void complete() {
+    _wait.complete();
+    _wait = null;
+  }
+
+  Future<bool> isPrimary(AssetId asset) {
+    return new Future.value(asset.extension == ".$from");
+  }
+
+  Future apply(Transform transform) {
+    numRuns++;
+    if (!_started.isCompleted) _started.complete();
+    _runningTransforms++;
+    return transform.primaryInput.then((input) {
+      for (var extension in to.split(" ")) {
+        var id = transform.primaryId.changeExtension(".$extension");
+        var content = input.readAsString() + ".$extension";
+        transform.addOutput(id, new MockAsset(id, content));
+
+      }
+
+      if (_wait != null) return _wait.future;
+    }).whenComplete(() {
+      _runningTransforms--;
+    });
+  }
+
+  String toString() => "$from->$to";
+}
+
+/// A [Transformer] that takes an input asset that contains a comma-separated
+/// list of paths and outputs a file for each path.
+class OneToManyTransformer extends Transformer {
+  final String extension;
+
+  /// The number of times the transformer has been applied.
+  int numRuns = 0;
+
+  /// Creates a transformer that consumes assets with [extension].
+  ///
+  /// That file contains a comma-separated list of paths and it will output
+  /// files at each of those paths.
+  OneToManyTransformer(this.extension);
+
+  Future<bool> isPrimary(AssetId asset) {
+    return new Future.value(asset.extension == ".$extension");
+  }
+
+  Future apply(Transform transform) {
+    numRuns++;
+    return transform.primaryInput.then((input) {
+      for (var line in input.readAsString().split(",")) {
+        var id = new AssetId(transform.primaryId.package, line);
+        transform.addOutput(id, new MockAsset(id, "spread $extension"));
+      }
+    });
+  }
+
+  String toString() => "1->many $extension";
+}
+
+/// A transformer that uses the contents of a file to define the other inputs.
+///
+/// Outputs a file with the same name as the primary but with an "out"
+/// extension containing the concatenated contents of all non-primary inputs.
+class ManyToOneTransformer extends Transformer {
+  final String extension;
+
+  /// The number of times the transformer has been applied.
+  int numRuns = 0;
+
+  /// Creates a transformer that consumes assets with [extension].
+  ///
+  /// That file contains a comma-separated list of paths and it will input
+  /// files at each of those paths.
+  ManyToOneTransformer(this.extension);
+
+  Future<bool> isPrimary(AssetId asset) {
+    return new Future.value(asset.extension == ".$extension");
+  }
+
+  Future apply(Transform transform) {
+    numRuns++;
+    return transform.primaryInput.then((primary) {
+      // Get all of the included inputs.
+      var inputs = primary.readAsString().split(",").map((path) {
+        var id = new AssetId(transform.primaryId.package, path);
+        return transform.getInput(id);
+      });
+
+      // Concatenate them to one output.
+      return Future.wait(inputs).then((inputs) {
+        var id = transform.primaryId.changeExtension(".out");
+        var contents = inputs.map((input) => input.readAsString()).join();
+        transform.addOutput(id, new MockAsset(id, contents));
+      });
+    });
+  }
+
+  String toString() => "many->1 $extension";
+}
+
+/// A transformer that throws an exception when run, after generating the
+/// given outputs.
+class BadTransformer extends Transformer {
+  /// The error it throws.
+  static const ERROR = "I am a bad transformer!";
+
+  /// The list of asset names that it should output.
+  final List<String> outputs;
+
+  BadTransformer(this.outputs);
+
+  Future<bool> isPrimary(AssetId asset) => new Future.value(true);
+  Future apply(Transform transform) {
+    return new Future(() {
+      // Create the outputs first.
+      for (var output in outputs) {
+        var id = new AssetId.parse(output);
+        transform.addOutput(id, new MockAsset(id, output));
+      }
+
+      // Then fail.
+      throw ERROR;
+    });
+  }
+}
+
+/// An implementation of [Asset] that never hits the file system.
+class MockAsset implements Asset {
+  final AssetId _id;
+  String _contents;
+
+  MockAsset(this._id, this._contents);
+
+  String readAsString() => _contents;
+  Stream<List<int>> read() => throw new UnimplementedError();
+
+  serialize() => throw new UnimplementedError();
+
+  String toString() => "MockAsset $_id $_contents";
+}