cleanup unused variables in tests

R=nweiz@google.com

Review URL: https://codereview.chromium.org//1216313003.
diff --git a/test/stream_group_test.dart b/test/stream_group_test.dart
index 727077c..db6c938 100644
--- a/test/stream_group_test.dart
+++ b/test/stream_group_test.dart
@@ -472,9 +472,8 @@
     });
 
     group("while active", () {
-      var subscription;
       setUp(() async {
-        subscription = streamGroup.stream.listen(null);
+        streamGroup.stream.listen(null);
         await flushMicrotasks();
       });
 
diff --git a/test/stream_zip_test.dart b/test/stream_zip_test.dart
index 9606b92..35ace7d 100644
--- a/test/stream_zip_test.dart
+++ b/test/stream_zip_test.dart
@@ -155,8 +155,6 @@
   });
 
   test("Pause/Resume", () {
-    var done = expectAsync((){});  // Call to complete test.
-
     int sc1p = 0;
     StreamController c1 = new StreamController(
       onPause: () {
@@ -174,6 +172,12 @@
       onResume: () {
         sc2p--;
       });
+
+    var done = expectAsync((){
+      expect(sc1p, equals(1));
+      expect(sc2p, equals(0));
+    });  // Call to complete test.
+
     Stream zip = new StreamZip([c1.stream, c2.stream]);
 
     const ms25 = const Duration(milliseconds: 25);
diff --git a/test/stream_zip_zone_test.dart b/test/stream_zip_zone_test.dart
index cdf2e16..47957a9 100644
--- a/test/stream_zip_zone_test.dart
+++ b/test/stream_zip_zone_test.dart
@@ -41,7 +41,6 @@
             expect(v, 37);
             expect(Zone.current, newZone1);
             runZoned(() {
-              Zone newZone2 = Zone.current;
               sub.onData(expectAsync((v) {
                 expect(v, 87);
                 expect(Zone.current, newZone1);