message: add simple test for reverse_iterator
diff: #include "clientversion.h"
  #include "primitives/transaction.h"
  +#include "reverse_iterator.h"
  #include "sync.h"
  #include "test/test_bitcoin.h"
  #include "test/test_random.h"
  @@ -856,4 +857,21 @@ BOOST_AUTO_TEST_CASE(enum_toString)
  BOOST_CHECK_EQUAL(toString(7, map2), "ALL");
  }
  +BOOST_AUTO_TEST_CASE(reverse_iterator)
  +{
  + std::vector<int> v = {5, 4, 3, 2, 1};
  + int cnt = 1;
  + for (auto x : reverse_iterate(v))
  + {
  + BOOST_CHECK_EQUAL(x, cnt);
  + cnt++;
  + }
  +
  + v = {}; // check empty vector
  + for (auto x : reverse_iterate(v))
  + {
  + BOOST_CHECK(x == 100); // should never get here but use x to avoid warning
  + }
  +}
  +
  BOOST_AUTO_TEST_SUITE_END()
  