Tighten types in test.dart even more.

tools/testing/dart/vendored_pkg/args/src/usage.dart

 // Copyright (c) 2013, 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 args.src.usage;
 
 import 'dart:math';
 
 import '../args.dart';
 
@@ skipping 126 matching lines @@
           title = max(title, getAllowedTitle(allowed).length);
         }
       }
     });
 
     // Leave a gutter between the columns.
     title += 4;
     columnWidths = [abbr, title];
   }
 
-  newline() {
+  void newline() {
     newlinesNeeded++;
     currentColumn = 0;
     numHelpLines = 0;
   }
 
-  write(int column, String text) {
+  void write(int column, String text) {
     var lines = text.split('\n');
 
     // Strip leading and trailing empty lines.
     while (lines.length > 0 && lines[0].trim() == '') {
       lines.removeRange(0, 1);
     }
 
     while (lines.length > 0 && lines[lines.length - 1].trim() == '') {
       lines.removeLast();
     }
 
     for (var line in lines) {
       writeLine(column, line);
     }
   }
 
-  writeLine(int column, String text) {
+  void writeLine(int column, String text) {
     // Write any pending newlines.
     while (newlinesNeeded > 0) {
       buffer.writeln('');
       newlinesNeeded--;
     }
 
     // Advance until we are at the right column (which may mean wrapping around
     // to the next line.
     while (currentColumn != column) {
       if (currentColumn < NUM_COLUMNS - 1) {
@@ skipping 20 matching lines @@
 
     // Keep track of how many consecutive lines we've written in the last
     // column.
     if (column == NUM_COLUMNS - 1) {
       numHelpLines++;
     } else {
       numHelpLines = 0;
     }
   }
 
-  buildAllowedList(Option option) {
+  String buildAllowedList(Option option) {
     var allowedBuffer = new StringBuffer();
     allowedBuffer.write('[');
     bool first = true;
     for (var allowed in option.allowed) {
       if (!first) allowedBuffer.write(', ');
       allowedBuffer.write(allowed);
       if (allowed == option.defaultValue) {
         allowedBuffer.write(' (default)');
       }
       first = false;
     }
     allowedBuffer.write(']');
     return allowedBuffer.toString();
   }
 }
 
 /** Pads [source] to [length] by adding spaces at the end. */
 String padRight(String source, int length) {
   final result = new StringBuffer();
   result.write(source);
 
   while (result.length < length) {
     result.write(' ');
   }
 
   return result.toString();
 }