[boost] [Boost.Test] Custom DataSet compiler error with no match for »operator^

Subject: [boost] [Boost.Test] Custom DataSet compiler error with no match for »operator^
From: Olaf Peter (ope-devel_at_[hidden])
Date: 2017-03-28 19:38:32

Hello,

I run into a compile problem with [Boost.Test] DataSet. I can reduce it 
by re-using the example provided by the docs:

http://www.boost.org/doc/libs/1_62_0/libs/test/doc/html/boost_test/tests_organization/test_cases/test_case_generation/datasets.html#boost_test.tests_organization.test_cases.test_case_generation.datasets.example_descr

#define  BOOST_TEST_MODULE  dataset_example68
#include  <boost/test/included/unit_test.hpp>
#include  <boost/test/data/test_case.hpp>
#include  <boost/test/data/monomorphic.hpp>
#include  <sstream>

namespace  bdata  =  boost::unit_test::data;

// Dataset generating a Fibonacci sequence
class  fibonacci_dataset  {
public:
     // Samples type is int
     using  sample=int;
     enum  {  arity  =  1  };

     struct  iterator  {

         iterator()  :  a(1),  b(1)  {}

         int  operator*()  const    {  return  b;  }
         void  operator++()
         {
             a  =  a  +  b;
             std::swap(a,  b);
         }
     private:
         int  a;
         int  b;  // b is the output
     };

     fibonacci_dataset()              {}

     // size is infinite
     bdata::size_t    size()  const     {  return  bdata::BOOST_TEST_DS_INFINITE_SIZE;  }

     // iterator
     iterator         begin()  const    {  return  iterator();  }
};

namespace  boost  {  namespace  unit_test  {  namespace  data  {  namespace  monomorphic  {
   // registering fibonacci_dataset as a proper dataset
   template  <>
   struct  is_dataset<fibonacci_dataset>  :  boost::mpl::true_  {};
}}}}

// Creating a test-driven dataset
BOOST_DATA_TEST_CASE(
     test1,
     fibonacci_dataset()  ^  fibonacci_dataset(),
     fib_sample,  exp)
{
       BOOST_TEST(fib_sample  ==  exp);
}

  error: no match for 'operator^' (operand types are 
'boost::unit_test::data::result_of::make<fibonacci_dataset>::type {aka 
fibonacci_dataset}' and 'fibonacci_dataset')
      fibonacci_dataset() ^ fibonacci_dataset(),

My use case has to load input and expect files provides by two datasets. 
How to fix it?

Thanks,

Olaf