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packages/barback/test/transformer/declare_assets.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.transformer.declare_asset;
+
+import 'package:barback/barback.dart';
+
+import 'mock.dart';
+
+/// A transformer that declares some outputs and emits others.
+class DeclareAssetsTransformer extends MockTransformer
+    implements DeclaringTransformer {
+  /// The assets that the transformer declares that it will emit.
+  final List<AssetId> declared;
+
+  /// The assets that the transformer actually emits.
+  ///
+  /// These assets' contents will be identical to their ids.
+  final List<AssetId> emitted;
+
+  /// If this is non-`null`, assets are only declared for this input.
+  final AssetId input;
+
+  DeclareAssetsTransformer(Iterable<String> declared, {Iterable<String> emitted,
+        String input})
+      : this.declared = declared.map((id) => new AssetId.parse(id)).toList(),
+        this.emitted = (emitted == null ? declared : emitted)
+            .map((id) => new AssetId.parse(id)).toList(),
+        this.input = input == null ? null : new AssetId.parse(input);
+
+  bool doIsPrimary(AssetId id) => input == null || id == input;
+
+  void doApply(Transform transform) {
+    for (var id in emitted) {
+      transform.addOutput(new Asset.fromString(id, id.toString()));
+    }
+  }
+
+  void declareOutputs(DeclaringTransform transform) {
+    declared.forEach(transform.declareOutput);
+  }
+}