- Extend the coin test for slightly different scenarios.

runtime/lib/math_patch.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.
 
 import "dart:typed_data";
 
 // A VM patch of the dart:math library.
 
 // If [x] is an [int] and [exponent] is a non-negative [int], the result is
 // an [int], otherwise the result is a [double].
@@ skipping 31 matching lines @@
 // TODO(iposva): Handle patch methods within a patch class correctly.
 patch class Random {
 
   /*patch*/ factory Random([int seed]) {
     if (seed == null) {
       seed = _Random._nextSeed();
     }
     do {
       seed = (seed + 0x5A17) & _Random._MASK_64;
     } while (seed == 0);
-    return new _Random._internal(seed);
+    // Crank a couple of times to distribute the seed bits a bit further.
+    return new _Random._internal(seed).._nextState()
+                                      .._nextState()
+                                      .._nextState()
+                                      .._nextState();
   }
 }
 
 
 class _Random implements Random {
   // Internal state of the random number generator.
   final _state = new Uint32List(2);
   static const kSTATE_LO = 0;
   static const kSTATE_HI = 1;
 
@@ skipping 57 matching lines @@
   static int _nextSeed() {
     if (_prng == null) {
       // TODO(iposva): Use system to get a random seed.
       _prng = new Random(new DateTime.now().millisecondsSinceEpoch);
     }
     // Trigger the PRNG once to change the internal state.
     _prng._nextState();
     return _prng._state[kSTATE_LO];
   }
 }