void InstancesTest::test_arrange_training_indices(void) 
{
   message += "test_arrange_training_indices\n";

   Instances i;

   Vector<size_t> training_indices;

   training_indices = i.arrange_training_indices();

   assert_true(training_indices.size() == 0, LOG);
   
   i.set(1);

   training_indices = i.arrange_training_indices();

   assert_true(training_indices.size() == 1, LOG);

}