Fix transformer tests.

These tests should never have passed, since they were closing a sink
before its controller emitted events.

R=cbracken@google.com

Review URL: https://codereview.chromium.org//2048473002 .

pkgs/stream_channel/pubspec.yaml

diff --git a/pkgs/stream_channel/pubspec.yaml b/pkgs/stream_channel/pubspec.yaml
index 3428dac..bcdfe8e 100644
--- a/pkgs/stream_channel/pubspec.yaml
+++ b/pkgs/stream_channel/pubspec.yaml
@@ -1,5 +1,5 @@
 name: stream_channel
-version: 1.5.0
+version: 1.5.1-dev
 description: An abstraction for two-way communication channels.
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/dart-lang/stream_channel

pkgs/stream_channel/test/stream_channel_test.dart

diff --git a/pkgs/stream_channel/test/stream_channel_test.dart b/pkgs/stream_channel/test/stream_channel_test.dart
index 2a6566a..41f4c32 100644
--- a/pkgs/stream_channel/test/stream_channel_test.dart
+++ b/pkgs/stream_channel/test/stream_channel_test.dart
@@ -41,13 +41,13 @@
     expect(sinkController.stream.toList(), completion(equals([4, 5, 6])));
   });
 
-  test("transform() transforms the channel", () {
+  test("transform() transforms the channel", () async {
     var transformed = channel.transform(
         new StreamChannelTransformer.fromCodec(UTF8));
 
     streamController.add([102, 111, 111, 98, 97, 114]);
     streamController.close();
-    expect(transformed.stream.toList(), completion(equals(["foobar"])));
+    expect(await transformed.stream.toList(), equals(["foobar"]));
 
     transformed.sink.add("fblthp");
     transformed.sink.close();
@@ -55,12 +55,12 @@
         completion(equals([[102, 98, 108, 116, 104, 112]])));
   });
 
-  test("transformStream() transforms only the stream", () {
+  test("transformStream() transforms only the stream", () async {
     var transformed = channel.transformStream(UTF8.decoder);
 
     streamController.add([102, 111, 111, 98, 97, 114]);
     streamController.close();
-    expect(transformed.stream.toList(), completion(equals(["foobar"])));
+    expect(await transformed.stream.toList(), equals(["foobar"]));
 
     transformed.sink.add("fblthp");
     transformed.sink.close();
@@ -68,14 +68,14 @@
         completion(equals(["fblthp"])));
   });
 
-  test("transformSink() transforms only the sink", () {
+  test("transformSink() transforms only the sink", () async {
     var transformed = channel.transformSink(
         new StreamSinkTransformer.fromStreamTransformer(UTF8.encoder));
 
     streamController.add([102, 111, 111, 98, 97, 114]);
     streamController.close();
-    expect(transformed.stream.toList(),
-        completion(equals([[102, 111, 111, 98, 97, 114]])));
+    expect(await transformed.stream.toList(),
+        equals([[102, 111, 111, 98, 97, 114]]));
 
     transformed.sink.add("fblthp");
     transformed.sink.close();