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_org... #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