Fix bug in Expect package's string compare.

pkg/expect/lib/expect.dart

 // Copyright (c) 2012, 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.
 
 /**
  * This library contains an Expect class with static methods that can be used
  * for simple unit-tests.
  */
 library expect;
 
@@ skipping 11 matching lines @@
    * The slice will contain at least the substring from [start] to the lower of
    * [end] and `start + length`.
    * If the result is no more than `length - 10` characters long,
    * context may be added by extending the range of the slice, by decreasing
    * [start] and increasing [end], up to at most length characters.
    * If the start or end of the slice are not matching the start or end of
    * the string, ellipses are added before or after the slice.
    * Control characters may be encoded as "\xhh" codes.
    */
   static String _truncateString(String string, int start, int end, int length) {
+    print("$string: $start: $end: $length");

[kasperl, 2013/05/31 08:14:22]

Did you really mean to submit this with the printing here and in line 72?

[kasperl, 2013/05/31 08:28:30]

Remove printing.

     if (end - start > length) {
       end = start + length;
     } else if (end - start < length) {
       int overflow = length - (end - start);
       if (overflow > 10) overflow = 10;
       // Add context.
       start = start - ((overflow + 1) ~/ 2);
       end = end + (overflow ~/ 2);
       if (start < 0) start = 0;
       if (end > string.length) end = string.length;
@@ skipping 16 matching lines @@
   }
 
   /**
    * Find the difference between two strings.
    *
    * This finds the first point where two strings differ, and returns
    * a text describing the difference.
    *
    * For small strings (length less than 20) nothing is done, and null is
    * returned. Small strings can be compared visually, but for longer strings
    * only a slice  containing the first difference will be shown.

[kasperl, 2013/05/31 08:28:30]

Remove one space after slice.

    */
   static String _stringDifference(String expected, String actual) {
+    print("digg: $expected, $actual");

[kasperl, 2013/05/31 08:28:30]

Remove printing.

     if (expected.length < 20 && actual.length < 20) return null;
     for (int i = 0; i < expected.length && i < actual.length; i++) {
       if (expected.codeUnitAt(i) != actual.codeUnitAt(i)) {
         int start = i;
         i++;
         while (i < expected.length && i < actual.length) {
           if (expected.codeUnitAt(i) == actual.codeUnitAt(i)) break;
+          i++;
         }
         int end = i;
         var truncExpected = _truncateString(expected, start, end, 20);
         var truncActual = _truncateString(actual, start, end, 20);
         return "at index $start: Expected <$truncExpected>, "
                                 "Found: <$truncActual>";
       }
     }
     return null;
   }
 
   /**
    * Checks whether the expected and actual values are equal (using `==`).
    */
   static void equals(var expected, var actual, [String reason = null]) {
     if (expected == actual) return;
     String msg = _getMessage(reason);
-    stringSpecialCase:
     if (expected is String && actual is String) {
       String stringDifference = _stringDifference(expected, actual);
       if (stringDifference != null) {
         _fail("Expect.equals($stringDifference$msg) fails.");
       }
     }
     _fail("Expect.equals(expected: <$expected>, actual: <$actual>$msg) fails.");
   }
 
   /**
@@ skipping 265 matching lines @@
 
 bool _identical(a, b) => identical(a, b);
 
 typedef bool _CheckExceptionFn(exception);
 
 class ExpectException implements Exception {
   ExpectException(this.message);
   String toString() => message;
   String message;
 }