Wrote functions to convert collections and maps to strings and invoked

tests/corelib/src/CollectionToStringTest.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.
 
 /**
  * Tests for the toString methods on collections (including maps).
  */
 
 // TODO(jjb): seed random number generator when API allows it
 
 final int NUM_TESTS = 3000;
-final int MAX_COLLECTION_SIZE = 6;
+final int MAX_COLLECTION_SIZE = 7;
 
 main() {
   smokeTest();
   exactTest();
   inexactTest();
 }
 
 
 /**
  * Test a few simple examples.
@@ skipping 38 matching lines @@
  * Generate a bunch of random collections (including Maps), and test that
  * there string form is as expected. The collections include collections
  * as elements, keys, and values, and include recursive references.
  *
  * This test restricts itself to collections with well-defined iteration
  * orders (i.e., no HashSet, HashMap).
  */
 void exactTest() {
   for (int i = 0; i < NUM_TESTS; i++) {
     // Choose a size from 0 to MAX_COLLECTION_SIZE, favoring larger sizes
-    float sqrtSize = Math.sqrt(Math.random() * (MAX_COLLECTION_SIZE + 1));
-    int size = (sqrtSize * sqrtSize).toInt();
-  
+    int size = Math.sqrt(random(MAX_COLLECTION_SIZE * MAX_COLLECTION_SIZE)).toInt();
+
     StringBuffer stringRep = new StringBuffer();
     Object o = randomCollection(size, stringRep, exact:true);
     Expect.equals(o.toString(), stringRep.toString());
   }
 }
 
 /**
  * Generate a bunch of random collections (including Maps), and test that
  * there string form is as expected. The collections include collections
  * as elements, keys, and values, and include recursive references.
  *
  * This test includes collections with ill-defined iteration orders (i.e.,
  * HashSet, HashMap). As a consequence, it can't use equality tests on the
  * string form. Instead, it performs equality tests on their "alphagrams."
  * This might allow false positives, but it does give a fair amount of
  * confidence.
  */
 void inexactTest() {
   for (int i = 0; i < NUM_TESTS; i++) {
     // Choose a size from 0 to MAX_COLLECTION_SIZE, favoring larger sizes
-    float sqrtSize = Math.sqrt(Math.random() * (MAX_COLLECTION_SIZE + 1));
-    int size = (sqrtSize * sqrtSize).toInt();
-  
+    int size = Math.sqrt(random(MAX_COLLECTION_SIZE * MAX_COLLECTION_SIZE)).toInt();
+
     StringBuffer stringRep = new StringBuffer();
     Object o = randomCollection(size, stringRep, exact:false);
     Expect.equals(alphagram(o.toString()), alphagram(stringRep.toString()));
   }
 }
 
 /**
  * Return a random collection (or Map) of the specified size, placing its
  * string representation into the given string buffer.
  *
@@ skipping 179 matching lines @@
 bool randomBool() {
   return Math.random() < .5;
 }
 
 /** Returns the alphabetized characters in a string. */
 String alphagram(String s) {
   List<int> chars = s.charCodes();
   chars.sort((int a, int b) => a - b);
   return new String.fromCharCodes(chars);
 }