tests: time_units: check for overflow in z_tmcvt intermediate

# Copyright 2022 Meta

# SPDX-License-Identifier: Apache-2.0

cmake_minimum_required(VERSION 3.20.0)

find_package(Zephyr COMPONENTS unittest REQUIRED HINTS $ENV{ZEPHYR_BASE})

project(time_units)

FILE(GLOB app_sources *.c)

target_sources(testbinary PRIVATE ${app_sources})

/*

 * Copyright 2022 Meta

 *

 * SPDX-License-Identifier: Apache-2.0

 */

#include <zephyr/ztest.h>

ZTEST_SUITE(time_units, NULL, NULL, NULL, NULL, NULL);

/*

 * Copyright 2022 Meta

 *

 * SPDX-License-Identifier: Apache-2.0

 */

#include <inttypes.h>

#include <limits.h>

#include <stdbool.h>

#include <stdint.h>

#include <zephyr/sys/time_units.h>

#include <zephyr/ztest.h>

/**

 * @brief Test @ref z_tmcvt for robustness against intermediate value overflow.

 *

 * With input

 * ```

 * [t0, t1, t2] = [

 *   UINT64_MAX / to_hz - 1,

 *   UINT64_MAX / to_hz,

 *   UINT64_MAX / to_hz + 1,

 * ]

 * ```

 *

 * passed through @ref z_tmcvt, we expect a linear sequence:

 * ```

 * [

 *   562949953369140,

 *   562949953399658,

 *   562949953430175,

 * ]

 * ```

 *

 * If an overflow occurs, we see something like the following:

 * ```

 * [

 *   562949953369140,

 *   562949953399658,

 *   8863,

 * ]

 * ```

 */

ZTEST(time_units, test_z_tmcvt_for_overflow)

{

	const uint32_t from_hz = 32768UL;

	const uint32_t to_hz = 1000000000UL;

	zassert_equal(562949953369140ULL,

		      z_tmcvt(UINT64_MAX / to_hz - 1, from_hz, to_hz, true, false, false, false));

	zassert_equal(562949953399658ULL,

		      z_tmcvt(UINT64_MAX / to_hz, from_hz, to_hz, true, false, false, false));

	zassert_equal(562949953430175ULL,

		      z_tmcvt(UINT64_MAX / to_hz + 1, from_hz, to_hz, true, false, false, false));

}

CONFIG_ZTEST=y

CONFIG_ZTEST_NEW_API=y

common:

  tags: time_units

  type: unit

tests:

  utilities.time_units.z_tmcvt: {}