Stop using deprecated pkg/test methods

Make corresponding pubspec changes w/ some other cleanup
diff --git a/pubspec.yaml b/pubspec.yaml
index dee5503..5a5193f 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,12 +1,12 @@
 name: crypto
-version: 2.0.1
+version: 2.0.2-dev
 author: Dart Team <misc@dartlang.org>
 description: Library of cryptographic functions.
 homepage: https://www.github.com/dart-lang/crypto
 environment:
-  sdk: '>=1.16.0-dev.5.0 <2.0.0'
+  sdk: '>=1.16.0 <2.0.0'
 dependencies:
   collection: '^1.0.0'
   convert: '>=1.0.0 <3.0.0'
 dev_dependencies:
-  test: '>=0.12.0 <0.13.0'
+  test: '^0.12.17'
diff --git a/test/sha1_test.dart b/test/sha1_test.dart
index 3b629b0..15dcea9 100644
--- a/test/sha1_test.dart
+++ b/test/sha1_test.dart
@@ -28,7 +28,7 @@
 
     test('close closes the underlying sink', () {
       var inner = new ChunkedConversionSink<Digest>.withCallback(
-          expectAsync((accumulated) {
+          expectAsync1((accumulated) {
         expect(accumulated.length, equals(1));
         expect(accumulated.first.toString(),
             equals("da39a3ee5e6b4b0d3255bfef95601890afd80709"));
diff --git a/test/sha256_test.dart b/test/sha256_test.dart
index 1c6653e..e653997 100644
--- a/test/sha256_test.dart
+++ b/test/sha256_test.dart
@@ -28,7 +28,7 @@
 
     test('close closes the underlying sink', () {
       var inner = new ChunkedConversionSink<Digest>.withCallback(
-          expectAsync((accumulated) {
+          expectAsync1((accumulated) {
         expect(accumulated.length, equals(1));
         expect(
             accumulated.first.toString(),