Allow multi-codeunit padding in String.padLeft/padRight.

tests/corelib/string_test.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.
 
 import "package:expect/expect.dart";
 
 void main() {
   testOutOfRange();
   testIllegalArgument();
   testConcat();
@@ skipping 393 matching lines @@
     "\u2028",
     "abcdef\u2028",
     "\u{10002}",
     "abcdef\u{10002}"
   ];
   List<int> counts = [
     0,
     1,
     2,
     3,
+    4,
+    5,
+    6,
+    7,
+    8,
+    9,
     10,
-    100
+    11,
+    12,
+    13,
+    14,
+    15,
+    16,
+    17,
+    127,
+    128,
+    129
   ];
-  void testRepeat(str, repeat, sep) {
+  void testRepeat(str, repeat) {
     String expect;
-    if (repeat == 0) {
+    if (repeat <= 0) {
       expect = "";
     } else if (repeat == 1) {
       expect = str;
     } else {
-      StringBuffer buf = new StringBuffer(str);
-      for (int i = 1; i < repeat; i++) {
-        buf.write(sep);
+      StringBuffer buf = new StringBuffer();
+      for (int i = 0; i < repeat; i++) {
         buf.write(str);
       }
       expect = buf.toString();
     }
-    String actual = str.repeat(repeat, sep);
+    String actual = str * repeat;
     Expect.equals(expect, actual,
-                  "$str#${str.length}*$repeat/$sep#${sep.length}");
+                  "$str#${str.length} * $repeat");
   }
   for (String str in testStrings) {
-    for (String sep in testStrings) {
-      for (int repeat in counts) {
-        testRepeat(str, repeat, sep);
-      }
+    for (int repeat in counts) {
+      testRepeat(str, repeat);
     }
   }
-  Expect.throws(() { "a".repeat(-1); });
 }
 
 void testPadLeft() {
   Expect.equals("    1", "1".padLeft(5, ' '));
   Expect.equals("   11", "11".padLeft(5, ' '));
   Expect.equals("  111", "111".padLeft(5, ' '));
   Expect.equals(" 1111", "1111".padLeft(5, ' '));
   Expect.equals("11111", "11111".padLeft(5, ' '));
   Expect.equals("111111", "111111".padLeft(5, ' '));
   Expect.equals("   \u{10002}", "\u{10002}".padLeft(5, ' '));
   Expect.equals('', ''.padLeft(0, 'a'));
   Expect.equals('a', ''.padLeft(1, 'a'));
   Expect.equals('aaaaa', ''.padLeft(5, 'a'));
   Expect.equals('', ''.padLeft(-2, 'a'));
 
-  Expect.throws(() { ' '.padLeft(5, ''); });
-  Expect.throws(() { ' '.padLeft(5, 'xx'); });
-  Expect.throws(() { ' '.padLeft(5, '\u{10002}'); });
+  Expect.equals('xyzxyzxyzxyzxyz', ''.padLeft(5, 'xyz'));
+  Expect.equals('xyzxyzxyzxyza', 'a'.padLeft(5, 'xyz'));
+  Expect.equals('xyzxyzxyzaa', 'aa'.padLeft(5, 'xyz'));
+  Expect.equals('\u{10002}\u{10002}\u{10002}aa', 'aa'.padLeft(5, '\u{10002}'));
+  Expect.equals('a', 'a'.padLeft(10, ''));
 }
 
 void testPadRight() {
   Expect.equals("1    ", "1".padRight(5, ' '));
   Expect.equals("11   ", "11".padRight(5, ' '));
   Expect.equals("111  ", "111".padRight(5, ' '));
   Expect.equals("1111 ", "1111".padRight(5, ' '));
   Expect.equals("11111", "11111".padRight(5, ' '));
   Expect.equals("111111", "111111".padRight(5, ' '));
   Expect.equals("\u{10002}   ", "\u{10002}".padRight(5, ' '));
   Expect.equals('', ''.padRight(0, 'a'));
   Expect.equals('a', ''.padRight(1, 'a'));
   Expect.equals('aaaaa', ''.padRight(5, 'a'));
   Expect.equals('', ''.padRight(-2, 'a'));
 
-  Expect.throws(() { ' '.padRight(5, ''); });
-  Expect.throws(() { ' '.padRight(5, 'xx'); });
-  Expect.throws(() { ' '.padRight(5, '\u{10002}'); });
+  Expect.equals('xyzxyzxyzxyzxyz', ''.padRight(5, 'xyz'));
+  Expect.equals('axyzxyzxyzxyz', 'a'.padRight(5, 'xyz'));
+  Expect.equals('aaxyzxyzxyz', 'aa'.padRight(5, 'xyz'));
+  Expect.equals('aa\u{10002}\u{10002}\u{10002}', 'aa'.padRight(5, '\u{10002}'));
+  Expect.equals('a', 'a'.padRight(10, ''));
 }