We will keep the main.cpp, sum_integers.cpp, and sum_integers.hpp unchanged from the previous recipes, but we will update test.cpp as a minimal example of a unit test using the Boost test library:

#include "sum_integers.hpp"
  
#include <vector>

#define BOOST_TEST_MODULE example_test_suite
#include <boost/test/unit_test.hpp>

BOOST_AUTO_TEST_CASE(add_example) {
  auto integers = {1, 2, 3, 4, 5};
  auto result = sum_integers(integers);
  BOOST_REQUIRE(result == 15);
}