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packages/barback/test/transformer/has_input.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.has_input;
+
+import 'dart:async';
+
+import 'package:barback/barback.dart';
+
+import 'mock.dart';
+
+/// Overwrites its primary inputs with descriptions of whether various secondary
+/// inputs exist.
+class HasInputTransformer extends MockTransformer {
+  /// The inputs whose existence will be checked.
+  final List<AssetId> inputs;
+
+  HasInputTransformer(Iterable<String> inputs)
+      : inputs = inputs.map((input) => new AssetId.parse(input)).toList();
+
+  bool doIsPrimary(AssetId id) => true;
+
+  Future doApply(Transform transform) {
+    return Future.wait(inputs.map((input) {
+      return transform.hasInput(input).then((hasInput) => "$input: $hasInput");
+    })).then((results) {
+      transform.addOutput(new Asset.fromString(
+          transform.primaryInput.id, results.join(', ')));
+    });
+  }
+
+  String toString() => "has inputs $inputs";
+}