Make String.startsWith take an optional start index.

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";
 
 // TODO(ngeoffray): test String methods with null arguments.
 class StringTest {
 
   static testMain() {
@@ skipping 109 matching lines @@
     Expect.isTrue("str".startsWith("str"));
 
     Expect.isFalse("str".startsWith("stri"));
     Expect.isFalse("str".startsWith("r"));
     Expect.isFalse("str".startsWith("tr"));
     Expect.isFalse("str".startsWith("t"));
 
     Expect.isTrue("".startsWith(""));
     Expect.isFalse("".startsWith("s"));
 
+    Expect.isFalse("strstr".startsWith("s", 1));
+    Expect.isFalse("strstr".startsWith("s", 2));
+    Expect.isTrue("strstr".startsWith("s", 3));
+    Expect.isFalse("strstr".startsWith("s", 4));
+
+    Expect.isFalse("strstr".startsWith("st", 1));
+    Expect.isFalse("strstr".startsWith("st", 2));
+    Expect.isTrue("strstr".startsWith("st", 3));
+    Expect.isFalse("strstr".startsWith("st", 4));
+
+    Expect.isFalse("strstr".startsWith("str", 1));
+    Expect.isFalse("strstr".startsWith("str", 2));
+    Expect.isTrue("strstr".startsWith("str", 3));
+    Expect.isFalse("strstr".startsWith("str", 4));
+
+    Expect.isTrue("str".startsWith("", 0));
+    Expect.isTrue("str".startsWith("", 1));
+    Expect.isTrue("str".startsWith("", 2));
+    Expect.isTrue("str".startsWith("", 3));
+
+    Expect.throws(() => "str".startsWith("", -1));
+    Expect.throws(() => "str".startsWith("", 4));
+
     var regexp = new RegExp("s(?:tr?)?");
     Expect.isTrue("s".startsWith(regexp));
     Expect.isTrue("st".startsWith(regexp));
     Expect.isTrue("str".startsWith(regexp));
     Expect.isTrue("sX".startsWith(regexp));
     Expect.isTrue("stX".startsWith(regexp));
     Expect.isTrue("strX".startsWith(regexp));
 
     Expect.isFalse("".startsWith(regexp));
     Expect.isFalse("astr".startsWith(regexp));
 
     Expect.isTrue("".startsWith(new RegExp("")));
     Expect.isTrue("".startsWith(new RegExp("a?")));
+
+    Expect.isFalse("strstr".startsWith(regexp, 1));
+    Expect.isFalse("strstr".startsWith(regexp, 2));
+    Expect.isTrue("strstr".startsWith(regexp, 3));
+    Expect.isFalse("strstr".startsWith(regexp, 4));
+
+    Expect.isTrue("str".startsWith(new RegExp(""), 0));
+    Expect.isTrue("str".startsWith(new RegExp(""), 1));
+    Expect.isTrue("str".startsWith(new RegExp(""), 2));
+    Expect.isTrue("str".startsWith(new RegExp(""), 3));
+    Expect.isTrue("str".startsWith(new RegExp("a?"), 0));
+    Expect.isTrue("str".startsWith(new RegExp("a?"), 1));
+    Expect.isTrue("str".startsWith(new RegExp("a?"), 2));
+    Expect.isTrue("str".startsWith(new RegExp("a?"), 3));

[floitsch, 2013/06/17 16:07:15]

Add test for RegExp with "^".

+
+    Expect.throws(() => "str".startsWith(regexp, -1));
+    Expect.throws(() => "str".startsWith(regexp, 4));
   }
 
   static testIndexOf() {
     Expect.equals(0, "str".indexOf("", 0));
     Expect.equals(0, "".indexOf("", 0));
     Expect.equals(-1, "".indexOf("a", 0));
 
     Expect.equals(1, "str".indexOf("t", 0));
     Expect.equals(1, "str".indexOf("tr", 0));
     Expect.equals(0, "str".indexOf("str", 0));
@@ skipping 190 matching lines @@
 
 void testStringLength(int length, String str) {
   Expect.equals(length, str.length);
   (length == 0 ? Expect.isTrue : Expect.isFalse)(str.isEmpty);
   (length != 0 ? Expect.isTrue : Expect.isFalse)(str.isNotEmpty);
 }
 
 main() {
   StringTest.testMain();
 }