libcruft-util/test/geom/sample/subregion.cpp

#include <cruft/util/tap.hpp>

#include <cruft/util/extent.hpp>
#include <cruft/util/geom/sample/subregion.hpp>


int
main ()
{
    cruft::TAP::logger tap;

    static const struct {
        cruft::extent2i shape;
        cruft::extent2i field;
        char const *message;
    } TESTS[] = {
        { {  1,  1 }, {   1,   1 }, "Unit shape and unit field" },
        { {  1,  1 }, { 100, 100 }, "Unit shape and large field" },
        { { 10, 10 }, { 100, 100 }, "Square shape and large field" },
        { {  1, 10 }, { 100, 100 }, "Tall shape and large field" },
        { { 10,  1 }, { 100, 100 }, "" },
        { {  2,  2 }, { 100, 100 }, "" },
    };

    static const int ITERATIONS = 1'000;

    for (auto const &[shape, field, msg]: TESTS) {
        cruft::rand::xoshiro256plusplus gen (42);
        cruft::geom::sample::subregion sampler {shape, field};

        cruft::region2i const valid (cruft::point2i (0), field);

        bool success = true;
        for (int i = 0; i < ITERATIONS; ++i) {
            auto const choice = sampler (gen);
            if (!valid.covers (choice)) {
                success = false;
                break;
            }
        }

        tap.expect (success, "subregion coverage validity, {}", msg);
    }

    return tap.status ();
}