Fix bug in Duration.toString.

sdk/lib/core/duration.dart

 // Copyright (c) 2011, 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.
 
 part of dart.core;
 
 /**
  * A span of time, such as 27 days, 4 hours, 12 minutes, and 3 seconds.
  *
  * To create a new Duration object, use this class's single constructor
  * giving the appropriate arguments:
  *
  *     Duration fastestMarathon = new Duration(hours:2, minutes:3, seconds:2);
  *
  * The Duration is the sum of all individual parts.
  * This means that individual parts can be larger than the next-bigger unit.
  * For example, [minutes] can be greater than 59.
  *
  *     assert(fastestMarathon.inMinutes == 123);
  *
  * All individual parts are allowed to be negative.
  *
  * Use one of the properties, such as [inDays],
  * to retrieve the integer value of the Duration in the specified time unit.
  * Note that the returned value is rounded down.
- * For example, 
+ * For example,
  *
  *     Duration aLongWeekend = new Duration(hours:88);
  *     assert(aLongWeekend.inDays == 3);
  *
  * This class provides a collection of arithmetic
  * and comparison operators,
  * plus a set of constants useful for converting time units.
  *
  * See [DateTime] to represent a point in time.
  * See [Stopwatch] to measure time-spans.
@@ skipping 179 matching lines @@
    * or a positive integer if it is greater.
    */
   int compareTo(Duration other) => _duration.compareTo(other._duration);
 
   String toString() {
     String sixDigits(int n) {
       if (n >= 100000) return "$n";
       if (n >= 10000) return "0$n";
       if (n >= 1000) return "00$n";
       if (n >= 100) return "000$n";
-      if (n > 10) return "0000$n";
+      if (n >= 10) return "0000$n";
       return "00000$n";
     }
     String twoDigits(int n) {
       if (n >= 10) return "$n";
       return "0$n";
     }
 
     if (inMicroseconds < 0) {
       Duration duration =
           new Duration(microseconds: -inMicroseconds);
       return "-$duration";
     }
     String twoDigitMinutes = twoDigits(inMinutes.remainder(MINUTES_PER_HOUR));
     String twoDigitSeconds = twoDigits(inSeconds.remainder(SECONDS_PER_MINUTE));
     String sixDigitUs =
         sixDigits(inMicroseconds.remainder(MICROSECONDS_PER_SECOND));
     return "$inHours:$twoDigitMinutes:$twoDigitSeconds.$sixDigitUs";
   }
 }