Wrote functions to convert collections and maps to strings and invoked

tests/corelib/src/CollectionToStringTest.dart

Index: tests/corelib/src/CollectionToStringTest.dart
===================================================================
--- tests/corelib/src/CollectionToStringTest.dart	(revision 4345)
+++ tests/corelib/src/CollectionToStringTest.dart	(working copy)
@@ -9,7 +9,7 @@
 // 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();
@@ -68,9 +68,8 @@
 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());
@@ -91,9 +90,8 @@
 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()));