Add placeholder test for completion domain.

pkg/analysis_server/test/integration/completion_domain_inttest.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.
 
 library test.integration.completion.domain;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_testing/reflective_tests.dart';
@@ skipping 26 matching lines @@
         // Since the feature doesn't work yet, just pause for a second to
         // collect the output of the analysis server, and then stop the test.
         // TODO(paulberry): finish writing the integration test once the feature
         // it more complete.
         return new Future.delayed(new Duration(seconds: 1), () {
           fail('test not completed yet');
         });
       });
     });
   }
+
+  test_placeholder() {
+    // The unit test framework freaks out if there are no tests, so this is a
+    // placeholder until we have a passing test.
+    // TODO(paulberry): remove this.
+  }
 }
 
 main() {
   runReflectiveTests(CompletionDomainIntegrationTest);
 }