//  Copyright Paul A. Bristow 2015.
//  Copyright Christopher Kormanyos 2015.
//  Distributed under the Boost Software License,
//  Version 1.0. (See accompanying file LICENSE_1_0.txt
//  or copy at http://www.boost.org/LICENSE_1_0.txt)

//! \file
/*!\brief Example of a Very Contrived Test for a list of types and their respective values.\n
It checks that the numeric_limits for the type is in accord with the expected value
that is contained in a dataset, array or list that can be indexed by the test_type.
*/

//! \sa http://www.boost.org/doc/libs/1_59_0/libs/test/doc/html/boost_test/tests_organization/test_cases/test_organization_templates.html#ref_BOOST_AUTO_TEST_CASE_TEMPLATE

#define BOOST_TEST_MODULE test_types_values
#define BOOST_LIB_DIAGNOSTIC

#include <boost/test/included/unit_test.hpp>
#include <boost/mpl/list.hpp> // for mpl::list

#include <array>
#include <limits>
#include <iostream>
#include <string>
#include <type_traits>

int index = 0; // Global so that can be accessed by digits_test

// List of types to test.
typedef boost::mpl::list<char, short, int, long, long long> test_types;

// Container for expected values of std::numeric_limits<T>::digits for the types above.
// It's size must match the size of the list of types to test.
std::array<const int, 5> type_values { { 8-1, 16-1, 32-1, 32-1, 64-1 } };
// Similarly OK for an array of any value type, including char
std::array<const char*, 5> type_strings { { "char", "short", "int", "long", "long long" } };
std::array<const std::string, 5> type_std_strings { { "char", "short", "int", "long", "long long" } };

template <typename T>
void digits_test()
{
  int digits = type_values[index]; // 8 if T == char, 16 if T == short, 32 if T == int ...
  BOOST_CHECK_EQUAL(std::numeric_limits<T>::digits, digits); // Test for corresponding value.
  index++;  // ready for next type.
  return;
} // void digits_test()

BOOST_AUTO_TEST_CASE_TEMPLATE(my_test, T, test_types)
{
  // Test for a value that is same for all T - works fine.
  BOOST_CHECK_EQUAL(std::numeric_limits<T>::radix, 2); 

  // Find the expected value for the type T from the array type_values.
    digits_test<T>();

} // BOOST_AUTO_TEST_CASE_TEMPLATE(my_test, T, test_types)


/*
Output:

Running 5 test cases...
1>
1>  *** No errors detected
*/