axmol/tests/unit-tests/Source/core/math/FastRNGTests.cpp

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#include <doctest.h>
#include <float.h>
#include "math/FastRNG.h"


TEST_SUITE("math/FastRNG") {
    TEST_CASE("rng") {
        auto rng = FastRNG(1);

        CHECK_EQ(622173, rng.rng());
        CHECK_EQ(1462482235, rng.rng());
        CHECK_EQ(3913629391, rng.rng());

        auto rng2 = FastRNG(2);

        CHECK_EQ(760312, rng2.rng());
        CHECK_EQ(2413601167, rng2.rng());
        CHECK_EQ(927245950, rng2.rng());
    }


    TEST_CASE("range") {
        auto rng = FastRNG(12345);

        CHECK_EQ(0, rng.range(0, 1));
        CHECK_EQ(-1, rng.range(-1, 0));
        CHECK_EQ(13, rng.range(10, 20));
        CHECK_EQ(12, rng.range(10, 20));
        CHECK_EQ(-11, rng.range(-20, -10));
        CHECK_EQ(-18, rng.range(-20, -10));

        CHECK_EQ(260724215, rng.range(-INT_MAX, INT_MAX));
        CHECK_EQ(1458015400, rng.range(-INT_MAX, INT_MAX));
    }


    TEST_CASE("rangeu") {
        auto rng = FastRNG(1);

        CHECK_EQ(0u, rng.rangeu(0u, 1u));
        CHECK_EQ(0u, rng.rangeu(0u, 1u));
        CHECK_EQ(19u, rng.rangeu(10u, 20u));

        CHECK_EQ(128334119, rng.rangeu(0u, UINT_MAX));
    }


    TEST_CASE("max") {
        auto rng = FastRNG(1);

        CHECK_EQ(0, rng.max(1));
        CHECK_EQ(3, rng.max(10));
        CHECK_EQ(1956814720, rng.max());
    }


    TEST_CASE("maxu") {
        auto rng = FastRNG(1);

        CHECK_EQ(0u, rng.maxu(1));
        CHECK_EQ(3u, rng.maxu(10));
        CHECK_EQ(3913629391, rng.maxu());
    }


    TEST_CASE("rangef") {
        auto rng = FastRNG(1);

        CHECK_EQ(doctest::Approx(-0.99971), rng.rangef(-1.0f, 1.0f));
        CHECK_EQ(doctest::Approx(-0.318979), rng.rangef(-1.0f, 1.0f));
        CHECK_EQ(doctest::Approx(19.1121), rng.rangef(10.0f, 20.0f));
        // These overflow
        //CHECK_EQ(doctest::Approx(1.0), rng.rangef(-FLT_MAX, FLT_MAX));
        //CHECK_EQ(doctest::Approx(1.0), rng.rangef(-FLT_MAX, FLT_MAX));
    }


    TEST_CASE("maxf") {
        auto rng = FastRNG(1);

        CHECK_EQ(doctest::Approx(0.000144861), rng.maxf(1.0f));
        CHECK_EQ(doctest::Approx(0.340511), rng.maxf(1.0f));
        CHECK_EQ(doctest::Approx(9.11213), rng.maxf(10.0f));
        CHECK_EQ(doctest::Approx(1.01677e+37), rng.maxf(FLT_MAX));
        CHECK_EQ(doctest::Approx(1.50114e+38), rng.maxf(FLT_MAX));
    }


    TEST_CASE("float01") {
        auto rng = FastRNG(1);

        CHECK_EQ(doctest::Approx(0.000144861), rng.float01());
        CHECK_EQ(doctest::Approx(0.340511), rng.float01());
        CHECK_EQ(doctest::Approx(0.911213), rng.float01());
        CHECK_EQ(doctest::Approx(0.0298801), rng.float01());
    }


    TEST_CASE("bool01") {
        auto rng = FastRNG(1);

        auto t = 0;
        auto f = 0;
        for (auto i = 0; i < 100; i++) {
            if (rng.bool01()) {
                t++;
            } else {
                f++;
            }
        }

        CHECK_EQ(45, t);
        CHECK_EQ(55, f);
    }
}