UsageException isn't called UsageError.

test/command_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:args/command_runner.dart';
 import 'package:test/test.dart';
 import 'utils.dart';
 
 void main() {
   var foo;
@@ skipping 72 matching lines @@
 -h, --help    Print this usage information.
 
 Available subcommands:
   aliased   Set a value.
 
 Run "test help" to see global options."""));
     });
   });
 
   test("usageException splits up the message and usage", () {
-    expect(() => foo.usageException("message"), throwsUsageError("message", """
+    expect(() => foo.usageException("message"),
+        throwsUsageException("message", """
 Usage: test foo [arguments]
 -h, --help    Print this usage information.
 
 Run "test help" to see global options."""));
   });
 
   test("considers a command hidden if all its subcommands are hidden", () {
     foo.addSubcommand(new HiddenCommand());
     expect(foo.hidden, isTrue);
   });
 }