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Diffstat (limited to 'tests/test_random_number_generator.h')
| -rw-r--r-- | tests/test_random_number_generator.h | 275 |
1 files changed, 275 insertions, 0 deletions
diff --git a/tests/test_random_number_generator.h b/tests/test_random_number_generator.h new file mode 100644 index 0000000000..39c4771c19 --- /dev/null +++ b/tests/test_random_number_generator.h @@ -0,0 +1,275 @@ +/*************************************************************************/ +/* test_random_number_generator.h */ +/*************************************************************************/ +/* This file is part of: */ +/* GODOT ENGINE */ +/* https://godotengine.org */ +/*************************************************************************/ +/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */ +/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md). */ +/* */ +/* Permission is hereby granted, free of charge, to any person obtaining */ +/* a copy of this software and associated documentation files (the */ +/* "Software"), to deal in the Software without restriction, including */ +/* without limitation the rights to use, copy, modify, merge, publish, */ +/* distribute, sublicense, and/or sell copies of the Software, and to */ +/* permit persons to whom the Software is furnished to do so, subject to */ +/* the following conditions: */ +/* */ +/* The above copyright notice and this permission notice shall be */ +/* included in all copies or substantial portions of the Software. */ +/* */ +/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */ +/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */ +/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/ +/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */ +/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */ +/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */ +/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ +/*************************************************************************/ + +#ifndef TEST_RANDOM_NUMBER_GENERATOR_H +#define TEST_RANDOM_NUMBER_GENERATOR_H + +#include "core/math/random_number_generator.h" +#include "tests/test_macros.h" + +namespace TestRandomNumberGenerator { + +TEST_CASE("[RandomNumberGenerator] Float") { + Ref<RandomNumberGenerator> rng = memnew(RandomNumberGenerator); + rng->set_seed(0); + + INFO("Should give float between 0.0 and 1.0."); + for (int i = 0; i < 1000; i++) { + real_t n = rng->randf(); + CHECK(n >= 0.0); + CHECK(n <= 1.0); + } +} + +TEST_CASE("[RandomNumberGenerator] Integer range via modulo") { + Ref<RandomNumberGenerator> rng = memnew(RandomNumberGenerator); + rng->set_seed(0); + + INFO("Should give integer between 0 and 100."); + for (int i = 0; i < 1000; i++) { + uint32_t n = rng->randi() % 100; + CHECK(n >= 0); + CHECK(n <= 100); + } +} + +TEST_CASE_MAY_FAIL("[RandomNumberGenerator] Integer 32 bit") { + Ref<RandomNumberGenerator> rng = memnew(RandomNumberGenerator); + rng->set_seed(0); // Change the seed if this fails. + + bool higher = false; + int i; + for (i = 0; i < 1000; i++) { + uint32_t n = rng->randi(); + if (n > 0x0fff'ffff) { + higher = true; + break; + } + } + INFO("Current seed: ", rng->get_seed()); + INFO("Current iteration: ", i); + CHECK_MESSAGE(higher, "Given current seed, this should give an integer higher than 0x0fff'ffff at least once."); +} + +TEST_CASE("[RandomNumberGenerator] Float and integer range") { + Ref<RandomNumberGenerator> rng = memnew(RandomNumberGenerator); + rng->set_seed(0); + uint64_t initial_state = rng->get_state(); + uint32_t initial_seed = rng->get_seed(); + + INFO("Should give float between -100.0 and 100.0, base test."); + for (int i = 0; i < 1000; i++) { + real_t n0 = rng->randf_range(-100.0, 100.0); + CHECK(n0 >= -100); + CHECK(n0 <= 100); + } + + rng->randomize(); + INFO("Should give float between -75.0 and 75.0."); + INFO("Shouldn't be affected by randomize."); + for (int i = 0; i < 1000; i++) { + real_t n1 = rng->randf_range(-75.0, 75.0); + CHECK(n1 >= -75); + CHECK(n1 <= 75); + } + + rng->set_state(initial_state); + INFO("Should give integer between -50 and 50."); + INFO("Shouldn't be affected by set_state."); + for (int i = 0; i < 1000; i++) { + real_t n2 = rng->randi_range(-50, 50); + CHECK(n2 >= -50); + CHECK(n2 <= 50); + } + + rng->set_seed(initial_seed); + INFO("Should give integer between -25 and 25."); + INFO("Shouldn't be affected by set_seed."); + for (int i = 0; i < 1000; i++) { + int32_t n3 = rng->randi_range(-25, 25); + CHECK(n3 >= -25); + CHECK(n3 <= 25); + } + + rng->randf(); + rng->randf(); + + INFO("Should give float between -10.0 and 10.0."); + INFO("Shouldn't be affected after generating new numbers."); + for (int i = 0; i < 1000; i++) { + real_t n4 = rng->randf_range(-10.0, 10.0); + CHECK(n4 >= -10); + CHECK(n4 <= 10); + } + + rng->randi(); + rng->randi(); + + INFO("Should give integer between -5 and 5."); + INFO("Shouldn't be affected after generating new numbers."); + for (int i = 0; i < 1000; i++) { + real_t n5 = rng->randf_range(-5, 5); + CHECK(n5 >= -5); + CHECK(n5 <= 5); + } +} + +TEST_CASE_MAY_FAIL("[RandomNumberGenerator] Normal distribution") { + Ref<RandomNumberGenerator> rng = memnew(RandomNumberGenerator); + rng->set_seed(1); // Change the seed if this fails. + INFO("Should give a number between -5 to 5 (5 std deviations away; above 99.7% chance it will be in this range)."); + INFO("Standard randfn function call."); + for (int i = 0; i < 100; i++) { + real_t n = rng->randfn(); + CHECK(n >= -5); + CHECK(n <= 5); + } + + INFO("Should give number between -5 to 5 after multiple randi/randf calls."); + INFO("5 std deviations away; above 99.7% chance it will be in this range."); + rng->randf(); + rng->randi(); + for (int i = 0; i < 100; i++) { + real_t n = rng->randfn(); + CHECK(n >= -5); + CHECK(n <= 5); + } + + INFO("Checks if user defined mean and deviation work properly."); + INFO("5 std deviations away; above 99.7% chance it will be in this range."); + for (int i = 0; i < 100; i++) { + real_t n = rng->randfn(5, 10); + CHECK(n >= -45); + CHECK(n <= 55); + } + + INFO("Checks if randfn works with changed seeds."); + INFO("5 std deviations away; above 99.7% chance it will be in this range."); + rng->randomize(); + for (int i = 0; i < 100; i++) { + real_t n = rng->randfn(3, 3); + CHECK(n >= -12); + CHECK(n <= 18); + } +} + +TEST_CASE("[RandomNumberGenerator] Zero for first number immediately after seeding") { + Ref<RandomNumberGenerator> rng = memnew(RandomNumberGenerator); + rng->set_seed(0); + uint32_t n1 = rng->randi(); + uint32_t n2 = rng->randi(); + INFO("Initial random values: ", n1, " ", n2); + CHECK(n1 != 0); + + rng->set_seed(1); + uint32_t n3 = rng->randi(); + uint32_t n4 = rng->randi(); + INFO("Values after changing the seed: ", n3, " ", n4); + CHECK(n3 != 0); +} + +TEST_CASE("[RandomNumberGenerator] Restore state") { + Ref<RandomNumberGenerator> rng = memnew(RandomNumberGenerator); + rng->randomize(); + uint64_t last_seed = rng->get_seed(); + INFO("Current seed: ", last_seed); + + rng->randi(); + rng->randi(); + + CHECK_MESSAGE(rng->get_seed() == last_seed, + "The seed should remain the same after generating some numbers"); + + uint64_t saved_state = rng->get_state(); + INFO("Current state: ", saved_state); + + real_t f1_before = rng->randf(); + real_t f2_before = rng->randf(); + INFO("This seed produces: ", f1_before, " ", f2_before); + + // Restore now. + rng->set_state(saved_state); + + real_t f1_after = rng->randf(); + real_t f2_after = rng->randf(); + INFO("Resetting the state produces: ", f1_after, " ", f2_after); + + String msg = "Should restore the sequence of numbers after resetting the state"; + CHECK_MESSAGE(f1_before == f1_after, msg); + CHECK_MESSAGE(f2_before == f2_after, msg); +} + +TEST_CASE("[RandomNumberGenerator] Restore from seed") { + Ref<RandomNumberGenerator> rng = memnew(RandomNumberGenerator); + rng->set_seed(0); + INFO("Current seed: ", rng->get_seed()); + uint32_t s0_1_before = rng->randi(); + uint32_t s0_2_before = rng->randi(); + INFO("This seed produces: ", s0_1_before, " ", s0_2_before); + + rng->set_seed(9000); + INFO("Current seed: ", rng->get_seed()); + uint32_t s9000_1 = rng->randi(); + uint32_t s9000_2 = rng->randi(); + INFO("This seed produces: ", s9000_1, " ", s9000_2); + + rng->set_seed(0); + INFO("Current seed: ", rng->get_seed()); + uint32_t s0_1_after = rng->randi(); + uint32_t s0_2_after = rng->randi(); + INFO("This seed produces: ", s0_1_after, " ", s0_2_after); + + String msg = "Should restore the sequence of numbers after resetting the seed"; + CHECK_MESSAGE(s0_1_before == s0_1_after, msg); + CHECK_MESSAGE(s0_2_before == s0_2_after, msg); +} + +TEST_CASE_MAY_FAIL("[RandomNumberGenerator] randi_range bias check") { + int zeros = 0; + int ones = 0; + Ref<RandomNumberGenerator> rng = memnew(RandomNumberGenerator); + for (int i = 0; i < 10000; i++) { + int val = rng->randi_range(0, 1); + val == 0 ? zeros++ : ones++; + } + CHECK_MESSAGE(abs(zeros * 1.0 / ones - 1.0) < 0.1, "The ratio of zeros to ones should be nearly 1"); + + int vals[10] = { 0 }; + for (int i = 0; i < 1000000; i++) { + vals[rng->randi_range(0, 9)]++; + } + + for (int i = 0; i < 10; i++) { + CHECK_MESSAGE(abs(vals[i] / 1000000.0 - 0.1) < 0.01, "Each element should appear roughly 10% of the time"); + } +} +} // namespace TestRandomNumberGenerator + +#endif // TEST_RANDOM_NUMBER_GENERATOR_H |