text:       
  #include "stdafx.h"
  
  BOOST_AUTO_TEST_CASE( sample_shuffle_t )  
  {
      using namespace flow;
  
      std::vector<int> ex = { 1 };
      auto s = from({ 1 }) | sample_shuffle(1);
      BOOST_CHECK_EQUAL_COLLECTIONS(ex.begin(), ex.end(), s.begin(), s.end());
  
      s = from({ 1, 1, 1, 1, 1 }) | sample_shuffle(1);
      BOOST_CHECK_EQUAL_COLLECTIONS(ex.begin(), ex.end(), s.begin(), s.end());
  
      s = from({ 1 }) | sample_shuffle(5);
      BOOST_CHECK_EQUAL_COLLECTIONS(ex.begin(), ex.end(), s.begin(), s.end());
  
      ex = {};
      s = empty<int>() | sample_shuffle(1);
      BOOST_CHECK_EQUAL_COLLECTIONS(ex.begin(), ex.end(), s.begin(), s.end());
  }
  
  