Add expectAsyncX and expectAsyncUntilX methods, and deprecate the old methods.

test/util/path_handler_test.dart

Index: test/util/path_handler_test.dart
diff --git a/test/util/path_handler_test.dart b/test/util/path_handler_test.dart
index 4ac0835d545fb62239cd6a994b557745c321f1b7..729b94ae1eebc35dd30524f89005a53c43c628ad 100644
--- a/test/util/path_handler_test.dart
+++ b/test/util/path_handler_test.dart
@@ -26,7 +26,7 @@ void main() {
 
   test("runs a handler for an exact URL", () async {
     var request = new shelf.Request("GET", Uri.parse("http://localhost/foo"));
-    handler.add("foo", expectAsync((request) {
+    handler.add("foo", expectAsync1((request) {
       expect(request.handlerPath, equals('/foo'));
       expect(request.url.path, isEmpty);
       return new shelf.Response.ok("good job!");
@@ -40,7 +40,7 @@ void main() {
   test("runs a handler for a suffix", () async {
     var request = new shelf.Request(
         "GET", Uri.parse("http://localhost/foo/bar"));
-    handler.add("foo", expectAsync((request) {
+    handler.add("foo", expectAsync1((request) {
       expect(request.handlerPath, equals('/foo/'));
       expect(request.url.path, 'bar');
       return new shelf.Response.ok("good job!");
@@ -55,13 +55,13 @@ void main() {
     var request = new shelf.Request(
         "GET", Uri.parse("http://localhost/foo/bar/baz"));
 
-    handler.add("foo", expectAsync((_) {}, count: 0));
-    handler.add("foo/bar", expectAsync((request) {
+    handler.add("foo", expectAsync1((_) {}, count: 0));
+    handler.add("foo/bar", expectAsync1((request) {
       expect(request.handlerPath, equals('/foo/bar/'));
       expect(request.url.path, 'baz');
       return new shelf.Response.ok("good job!");
     }));
-    handler.add("foo/bar/baz/bang", expectAsync((_) {}, count: 0));
+    handler.add("foo/bar/baz/bang", expectAsync1((_) {}, count: 0));
 
     var response = await _handle(request);
     expect(response.statusCode, equals(200));