Respect top-level @TestOn declarations.

bin/unittest.dart

 // Copyright (c) 2015, 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 unittest.unittest;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:isolate';
 
@@ skipping 60 matching lines @@
       if (new File(path).existsSync()) return loader.loadFile(path);
       throw new LoadException(path, 'Does not exist.');
     }));
   }).then((suites) {
     var reporter = new CompactReporter(flatten(suites), color: color);
     return reporter.run().then((success) {
       exitCode = success ? 0 : 1;
     }).whenComplete(() => reporter.close());
   }).catchError((error, stackTrace) {
     if (error is LoadException) {
-      // TODO(nweiz): color this message?
-      stderr.writeln(getErrorMessage(error));
+      stderr.writeln(error.toString(color: color));
 
       // Only print stack traces for load errors that come from the user's 
       if (error.innerError is! IOException &&
           error.innerError is! IsolateSpawnException &&
+          error.innerError is! FormatException &&
           error.innerError is! String) {
         stderr.write(terseChain(stackTrace));
       }
 
       exitCode = error.innerError is IOException
           ? exit_codes.io
           : exit_codes.data;
     } else {
       stderr.writeln(getErrorMessage(error));
       stderr.writeln(new Trace.from(stackTrace).terse);
@@ skipping 25 matching lines @@
     output = stderr;
   }
 
   output.write("""$message
 
 Usage: pub run unittest:unittest [files or directories...]
 
 ${_parser.usage}
 """);
 }