Roll Observatory deps (charted -> ^0.3.0)

packages/usage/test/usage_impl_test.dart

Index: packages/usage/test/usage_impl_test.dart
diff --git a/packages/usage/test/usage_impl_test.dart b/packages/usage/test/usage_impl_test.dart
index 8601ceef83e6c4d983f4770ad4de990f9f860ff6..b8c0f052cdb41cf43da482f806178d6f73817599 100644
--- a/packages/usage/test/usage_impl_test.dart
+++ b/packages/usage/test/usage_impl_test.dart
@@ -4,11 +4,13 @@
 
 library usage.impl_test;
 
-import 'package:unittest/unittest.dart';
+import 'package:test/test.dart';
 import 'package:usage/src/usage_impl.dart';
 
 import 'src/common.dart';
 
+main() => defineTests();
+
 void defineTests() {
   group('ThrottlingBucket', () {
     test('can send', () {
@@ -64,7 +66,7 @@ void defineTests() {
 
   group('postEncode', () {
     test('simple', () {
-      Map map = {'foo': 'bar', 'baz': 'qux norf'};
+      Map<String, dynamic> map = {'foo': 'bar', 'baz': 'qux norf'};
       expect(postEncode(map), 'foo=bar&baz=qux%20norf');
     });
   });