Clean up barback tests.

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 '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;
 
+MockProvider _provider;
+AssetGraph _graph;
+
+/// 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;

[nweiz, 2013/06/27 23:12:20]

Apparently we have a StreamIterator class, which seems applicable here.

[Bob Nystrom, 2013/07/02 21:41:28]

I tried that, but it doesn't allow queueing up multiple requests. If you call
moveNext() again before the future returned by the first moveNext() call
completes, it throws an error.

[nweiz, 2013/07/03 00:40:35]

Gross. File a bug?

[Bob Nystrom, 2013/07/03 17:12:16]

It's the documented behavior. :-/

[nweiz, 2013/07/03 18:17:15]

Then file a feature request? It's good to have these things documented so when
other people try to do the same thing they can add their voices.

+
 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]) {
+/// 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]) {
+  if (assets == null) assets = [];
+  if (transformers == null) transformers = [];
+
+  _provider = new MockProvider(assets);
+  _graph = new AssetGraph(_provider, transformers);
+  _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);
+}
+
+/// 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);
+}
+
+/// 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");
+}
+
+/// 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");
+}
+
+/// Expects that the next [BuildResult] is a build success.
+void buildShouldSucceed([void callback()]) {
+  _graph.results.elementAt(_nextBuildResult++).then(wrapAsync((result) {

[nweiz, 2013/06/27 23:12:20]

I strongly prefer expect(..., completes) to [wrapAsync] when using futures. With
[wrapAsync], if [elementAt] fails for any reason, that error will be
top-leveled.

[Bob Nystrom, 2013/07/02 21:41:28]

Done.

+    expect(result.succeeded, isTrue);
+    if (callback != null) callback();
+  }));
+}
+
+/// Expects that the next [BuildResult] emitted is a failure.
+///
+/// Invokes [callback] with the error (not the result) so that it can provide
+/// more precise expectations.
+void buildShouldFail(void callback(error)) {
+  _graph.results.elementAt(_nextBuildResult++).then(wrapAsync((result) {
+    expect(result.succeeded, isFalse);
+    callback(result.error);
+  }));
+}
+
+/// Pauses the schedule until the currently running build completes.
+void waitForBuild() {

[nweiz, 2013/06/27 23:12:20]

Isn't it possible that a build emits an error before it finishes? Even if it's
not now, it will be in the future, right?

[Bob Nystrom, 2013/07/02 21:41:28]

Yup. Modified this to check that the result is actually a build success.

+  schedule(() {
+    return _graph.results.first;

[nweiz, 2013/06/27 23:12:20]

Style nit: =>

[Bob Nystrom, 2013/07/02 21:41:28]

Invalidated by above change.

+  });
+}
+
+/// 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 _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) {
+/// 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 _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) {
+/// Expects that the next [BuildResult] is an output file collision error on an
+/// asset matching [name].
+Future expectCollision(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");
+  _graph.results.first.then(wrapAsync((result) {
+    expect(result.error, new isInstanceOf<AssetCollisionException>());
+    expect(result.error.id, equals(id));
+  }));
 }
 
-/// Expects that [graph] will have an error on an asset matching [name] for
-/// missing [input].
+/// 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");
 }
 
 /// 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.
+  /// The completer that [getAsset()] is waiting on to complete when paused.
   ///
   /// If `null` it will return the asset immediately.
-  Completer _wait;
+  Completer _pauseCompleter;
 
   /// 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 _pause() {
+    _pauseCompleter = new Completer();
   }
 
-  void complete() {
-    _wait.complete();
-    _wait = null;
+  void _resume() {
+    _pauseCompleter.complete();
+    _pauseCompleter = 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) {
+  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;
+    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,
           orElse: () => throw new AssetNotFoundException(id));
@@ skipping 177 matching lines @@
 
   MockAsset(this._id, this._contents);
 
   String readAsString() => _contents;
   Stream<List<int>> read() => throw new UnimplementedError();
 
   serialize() => throw new UnimplementedError();
 
   String toString() => "MockAsset $_id $_contents";
 }