sdk/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";
}