TEST_F(HeaderTableTests, index_translation) {
  // simple cases
  length_ = 10;
  head_ = 5;
  xcheck(0, 6);
  xcheck(3, 3);
  xcheck(5, 1);

  // wrap
  head_ = 1;
  xcheck(0, 2);
  xcheck(8, 4);
  xcheck(5, 7);
}
TEST_F(HeaderTableTests, index_translation) {
   
  length_ = 10;
  head_ = 5;
  xcheck(0, 6);
  xcheck(3, 3);
  xcheck(5, 1);

   
  head_ = 1;
  xcheck(0, 2);
  xcheck(8, 4);
  xcheck(5, 7);
}