Add an AssetStream class to Barback.

pkg/barback/test/asset_test.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.asset_test;
 
 import 'dart:async';
 import 'dart:convert' show Encoding, UTF8, LATIN1;
 import 'dart:io';
 import 'dart:utf';
@@ skipping 55 matching lines @@
     });
   });
 
   group("Asset.fromString", () {
     test("returns an asset with the given ID", () {
       var asset = new Asset.fromString(id, "content");
       expect(asset.id, equals(id));
     });
   });
 
+  group("Asset.fromStream", () {
+    test("returns an asset with the given ID", () {
+      var asset = new Asset.fromStream(id,
+          new Stream.fromFuture(new Future.value([104, 101, 108, 108, 111])));
+      expect(asset.id, equals(id));
+    });
+  });
+
   group("read()", () {
     test("gets the UTF-8-encoded string for a string asset", () {
       var asset = new Asset.fromString(id, "çøñ†éℵ™");
       expect(asset.read().toList(),
           completion(equals([encodeUtf8("çøñ†éℵ™")])));
     });
 
     test("gets the raw bytes for a byte asset", () {
       var asset = new Asset.fromBytes(id, binaryContents);
       expect(asset.read().toList(),
           completion(equals([binaryContents])));
     });
 
     test("gets the raw bytes for a binary file", () {
       var asset = new Asset.fromPath(id, binaryFilePath);
       expect(asset.read().toList(),
           completion(equals([binaryContents])));
     });
 
     test("gets the raw bytes for a text file", () {
       var asset = new Asset.fromPath(id, textFilePath);
       expect(asset.read().toList(),
           completion(equals([encodeUtf8("çøñ†éℵ™")])));
     });
+
+    test("gets the raw bytes for a stream", () {
+      var asset = new Asset.fromStream(id,
+          new Stream.fromFuture(new Future.value(encodeUtf8("çøñ†éℵ™"))));
+      expect(asset.read().toList(),
+          completion(equals([encodeUtf8("çøñ†éℵ™")])));
+    });
   });
 
   group("readAsString()", () {
     group("byte asset", () {
       test("defaults to UTF-8 if encoding is omitted", () {
         var asset = new Asset.fromBytes(id, encodeUtf8("çøñ†éℵ™"));
         expect(asset.readAsString(),
             completion(equals("çøñ†éℵ™")));
       });
 
@@ skipping 20 matching lines @@
       });
     });
 
     group("file asset", () {
       test("defaults to UTF-8 if encoding is omitted", () {
         var asset = new Asset.fromPath(id, textFilePath);
         expect(asset.readAsString(),
             completion(equals("çøñ†éℵ™")));
       });
     });
+
+    group("stream asset", () {
+      test("defaults to UTF-8 if encoding is omitted", () {
+        var asset = new Asset.fromStream(id,
+            new Stream.fromFuture(new Future.value(encodeUtf8("çøñ†éℵ™"))));
+        expect(asset.readAsString(),
+            completion(equals("çøñ†éℵ™")));
+      });
+
+      test("supports UTF-8", () {
+        var asset = new Asset.fromStream(id,
+            new Stream.fromFuture(new Future.value(encodeUtf8("çøñ†éℵ™"))));
+        expect(asset.readAsString(encoding: UTF8),
+            completion(equals("çøñ†éℵ™")));
+      });
+
+      // TODO(nweiz): Test other encodings once #6284 is fixed.

[Bob Nystrom, 2013/08/27 17:20:29]

Add some tests for how it handles the source stream emitting values over time.
In particular:

- If a stream emits values before the asset is read, they are captured by the
asset.
- Reading the asset multiple times replays the stream.
- Reading doesn't complete until the source stream is closed.

[nweiz, 2013/08/27 17:47:52]

These are essentially the tests we already have for StreamReplayer. I don't
think we'd get value from duplicating them here, any more than we'd get value
from testing basic Stream functionality here.

+    });
   });
 
   group("toString()", () {
     group("byte asset", () {
       test("shows the list of bytes in hex", () {
         var asset = new Asset.fromBytes(id,
             [0, 1, 2, 4, 8, 16, 32, 64, 128, 255]);
         expect(asset.toString(), equals(
             "Bytes [00 01 02 04 08 10 20 40 80 ff]"));
       });
@@ skipping 22 matching lines @@
     });
 
     group("file asset", () {
       test("shows the file path", () {
         var asset = new Asset.fromPath(id, "path.txt");
         expect(asset.toString(), equals('File "path.txt"'));
       });
     });
   });
 }