saltylab-firmware/test/test_battery_coulomb.c

/*
 * test_battery_coulomb.c — Battery coulomb counter unit tests (Issue #325)
 *
 * Verifies:
 *   - coulomb_init() initialization and state reset
 *   - coulomb_tick() integration accuracy with simulated INA219 readings
 *   - SOC calculation (0–100%) against known discharge profiles
 *   - Flash read/write operations with magic checksum validation
 *   - Cycle tracking and depth-of-discharge (DOD) computation
 *   - Calibration offset/scale application and persistence
 *   - Charging vs. discharging state detection
 *   - Boundary conditions and saturation
 */

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <math.h>

/* ══════════════════════════════════════════════════════════════════════════ */
/* BATTERY COULOMB COUNTER CONSTANTS (from header)                           */
/* ══════════════════════════════════════════════════════════════════════════ */

#define BATTERY_CAPACITY_MAH    2200
#define BATTERY_CAPACITY_Q      (BATTERY_CAPACITY_MAH / 3.6f)  /* ~611 coulombs */

#define INA219_I2C_ADDR         0x40
#define INA219_SHUNT_OHM        0.01f
#define INA219_MAX_CURRENT_A    3.2f

#define COULOMB_SAMPLE_RATE_HZ  1000
#define COULOMB_INTEGRATION_S   1.0f

#define COULOMB_FLASH_ADDR      0x0800D000
#define COULOMB_FLASH_SIZE      4096

/* ══════════════════════════════════════════════════════════════════════════ */
/* DATA STRUCTURES (from header)                                              */
/* ══════════════════════════════════════════════════════════════════════════ */

typedef struct {
    float current_a;
    float coulombs_total;
    float coulombs_discharged;
    float soc_percent;
    uint32_t tick_count;
    bool charging;
    uint16_t cycle_count;
} coulomb_state_t;

typedef struct {
    uint32_t magic;
    float current_offset_a;
    float current_scale;
    uint32_t total_cycles;
    uint32_t timestamp;
    uint16_t reserved[6];
} coulomb_calibration_t;

typedef struct {
    float coulombs_capacity;
    float depth_of_discharge;
    uint32_t duration_s;
    float avg_current_a;
} coulomb_cycle_t;

/* ══════════════════════════════════════════════════════════════════════════ */
/* SIMULATOR & MOCKS                                                          */
/* ══════════════════════════════════════════════════════════════════════════ */

/* Mock INA219 readings (raw ADC values) */
static int16_t mock_ina219_current_raw = 0;

/* Mock flash storage (simulated 4KB sector) */
static uint8_t mock_flash[COULOMB_FLASH_SIZE];

/* Simulated coulomb counter state */
static coulomb_state_t g_coulomb_state = {0};
static coulomb_calibration_t g_calibration = {0};

#define COULOMB_CYCLE_HISTORY_SIZE 16
static coulomb_cycle_t g_cycle_history[COULOMB_CYCLE_HISTORY_SIZE];
static uint8_t g_cycle_write_idx = 0;

/* Runtime simulation variables */
static float g_battery_capacity_q = BATTERY_CAPACITY_Q;

/* ──────────────────────────────────────────────────────────────────────────*/
/* Mock I2C / INA219 Functions                                               */
/* ──────────────────────────────────────────────────────────────────────────*/

static int mock_i2c_write_reg(uint8_t addr, uint8_t reg, uint16_t value) {
    /* Simulate INA219 register write */
    if (addr != INA219_I2C_ADDR) return -1;
    return 0;
}

static int mock_i2c_read_reg(uint8_t addr, uint8_t reg, uint16_t *out_value) {
    /* Simulate INA219 current register read */
    if (addr != INA219_I2C_ADDR) return -1;
    *out_value = mock_ina219_current_raw;
    return 0;
}

static int mock_ina219_init(void) {
    /* Simulate INA219 config via I2C */
    mock_i2c_write_reg(INA219_I2C_ADDR, 0x00, 0x399F);  /* Config register */
    mock_i2c_write_reg(INA219_I2C_ADDR, 0x05, 0x0800);  /* Calibration */
    return 0;
}

static int16_t mock_ina219_read_current_raw(void) {
    uint16_t raw = 0;
    mock_i2c_read_reg(INA219_I2C_ADDR, 0x01, &raw);
    return (int16_t)raw;
}

/* ──────────────────────────────────────────────────────────────────────────*/
/* Mock Flash Functions                                                       */
/* ──────────────────────────────────────────────────────────────────────────*/

static int mock_flash_write(uint32_t addr, const void *data, uint16_t len) {
    if (addr < COULOMB_FLASH_ADDR || (addr + len) > (COULOMB_FLASH_ADDR + COULOMB_FLASH_SIZE)) {
        return -1;
    }
    uint32_t offset = addr - COULOMB_FLASH_ADDR;
    memcpy(&mock_flash[offset], data, len);
    return 0;
}

static int mock_flash_read(uint32_t addr, void *data, uint16_t len) {
    if (addr < COULOMB_FLASH_ADDR || (addr + len) > (COULOMB_FLASH_ADDR + COULOMB_FLASH_SIZE)) {
        return -1;
    }
    uint32_t offset = addr - COULOMB_FLASH_ADDR;
    memcpy(data, &mock_flash[offset], len);
    return 0;
}

static int mock_flash_erase_sector(uint32_t addr) {
    if (addr < COULOMB_FLASH_ADDR || addr >= (COULOMB_FLASH_ADDR + COULOMB_FLASH_SIZE)) {
        return -1;
    }
    memset(mock_flash, 0xFF, COULOMB_FLASH_SIZE);
    return 0;
}

/* ══════════════════════════════════════════════════════════════════════════ */
/* COULOMB COUNTER IMPLEMENTATION (for testing)                              */
/* ══════════════════════════════════════════════════════════════════════════ */

static int coulomb_init_test(uint16_t capacity_mah) {
    g_battery_capacity_q = capacity_mah / 3.6f;
    memset(&g_coulomb_state, 0, sizeof(g_coulomb_state));
    memset(&g_calibration, 0, sizeof(g_calibration));
    memset(g_cycle_history, 0, sizeof(g_cycle_history));
    g_cycle_write_idx = 0;

    if (mock_ina219_init() != 0) return -1;

    /* Load calibration from mock flash */
    if (mock_flash_read(COULOMB_FLASH_ADDR, &g_calibration, sizeof(g_calibration)) == 0) {
        if (g_calibration.magic != 0xCAFEBABE) {
            /* No valid calibration, use defaults */
            g_calibration.magic = 0xCAFEBABE;
            g_calibration.current_offset_a = 0.0f;
            g_calibration.current_scale = 1.0f;
            g_calibration.total_cycles = 0;
        }
    }

    g_coulomb_state.soc_percent = 100.0f;
    return 0;
}

static void coulomb_tick_test(void) {
    int16_t raw = mock_ina219_read_current_raw();
    float current_a = (raw * 0.0001f) + g_calibration.current_offset_a;
    current_a *= g_calibration.current_scale;

    g_coulomb_state.current_a = current_a;
    g_coulomb_state.charging = (current_a < 0.0f);

    /* Integration: dt = 1ms */
    float dt_s = 1.0f / COULOMB_SAMPLE_RATE_HZ;
    float coulombs_delta = current_a * dt_s;

    g_coulomb_state.coulombs_total += coulombs_delta;

    /* Discharging threshold: 50mA */
    if (current_a > 0.05f) {
        g_coulomb_state.coulombs_discharged += coulombs_delta;
    }

    /* SOC calculation */
    g_coulomb_state.soc_percent = 100.0f * (1.0f - (g_coulomb_state.coulombs_discharged / g_battery_capacity_q));
    if (g_coulomb_state.soc_percent < 0.0f) g_coulomb_state.soc_percent = 0.0f;
    if (g_coulomb_state.soc_percent > 100.0f) g_coulomb_state.soc_percent = 100.0f;

    g_coulomb_state.tick_count++;
}

static float coulomb_get_soc_test(void) {
    return g_coulomb_state.soc_percent;
}

static float coulomb_get_current_a_test(void) {
    return g_coulomb_state.current_a;
}

static float coulomb_get_coulombs_discharged_test(void) {
    return g_coulomb_state.coulombs_discharged;
}

static uint16_t coulomb_get_cycle_count_test(void) {
    return g_coulomb_state.cycle_count;
}

static void coulomb_mark_full_charge_test(void) {
    g_coulomb_state.coulombs_discharged = 0.0f;
    g_coulomb_state.soc_percent = 100.0f;
}

static void coulomb_mark_fully_discharged_test(void) {
    g_coulomb_state.coulombs_discharged = g_battery_capacity_q;
    g_coulomb_state.soc_percent = 0.0f;
    g_coulomb_state.cycle_count++;
}

static void coulomb_set_soc_test(float soc_percent) {
    if (soc_percent < 0.0f) soc_percent = 0.0f;
    if (soc_percent > 100.0f) soc_percent = 100.0f;
    g_coulomb_state.soc_percent = soc_percent;
    g_coulomb_state.coulombs_discharged = g_battery_capacity_q * (1.0f - (soc_percent / 100.0f));
}

static int coulomb_save_calibration_test(void) {
    g_calibration.magic = 0xCAFEBABE;
    return mock_flash_write(COULOMB_FLASH_ADDR, &g_calibration, sizeof(g_calibration));
}

static int coulomb_load_calibration_test(void) {
    coulomb_calibration_t tmp;
    if (mock_flash_read(COULOMB_FLASH_ADDR, &tmp, sizeof(tmp)) != 0) return -1;
    if (tmp.magic != 0xCAFEBABE) return -1;
    g_calibration = tmp;
    return 0;
}

static int coulomb_factory_reset_test(void) {
    mock_flash_erase_sector(COULOMB_FLASH_ADDR);
    memset(&g_coulomb_state, 0, sizeof(g_coulomb_state));
    memset(&g_calibration, 0, sizeof(g_calibration));
    g_coulomb_state.soc_percent = 100.0f;
    return 0;
}

/* ══════════════════════════════════════════════════════════════════════════ */
/* UNIT TEST FRAMEWORK                                                        */
/* ══════════════════════════════════════════════════════════════════════════ */

static int test_count = 0, test_passed = 0, test_failed = 0;

#define TEST(name) do { test_count++; printf("\n  TEST %d: %s\n", test_count, name); } while(0)
#define ASSERT(cond, msg) do { \
    if (cond) { \
        test_passed++; \
        printf("    ✓ %s\n", msg); \
    } else { \
        test_failed++; \
        printf("    ✗ %s\n", msg); \
    } \
} while(0)

#define ASSERT_FLOAT(val, expected, tol, msg) do { \
    float diff = (val) - (expected); \
    if (diff < 0) diff = -diff; \
    if (diff <= (tol)) { \
        test_passed++; \
        printf("    ✓ %s (%.4f ≈ %.4f)\n", msg, val, expected); \
    } else { \
        test_failed++; \
        printf("    ✗ %s (%.4f ≠ %.4f, diff=%.4f)\n", msg, val, expected, diff); \
    } \
} while(0)

/* ══════════════════════════════════════════════════════════════════════════ */
/* TEST CASES                                                                 */
/* ══════════════════════════════════════════════════════════════════════════ */

void test_initialization(void) {
    TEST("Initialization and state reset");
    coulomb_init_test(2200);

    ASSERT(g_coulomb_state.current_a == 0.0f, "Current starts at 0A");
    ASSERT(g_coulomb_state.coulombs_total == 0.0f, "Total coulombs starts at 0");
    ASSERT(g_coulomb_state.coulombs_discharged == 0.0f, "Discharged coulombs starts at 0");
    ASSERT_FLOAT(g_coulomb_state.soc_percent, 100.0f, 0.1f, "SOC starts at 100%");
    ASSERT(g_coulomb_state.tick_count == 0, "Tick count starts at 0");
    ASSERT(g_coulomb_state.charging == false, "Not charging initially");
    ASSERT(g_coulomb_state.cycle_count == 0, "Cycle count starts at 0");
}

void test_coulomb_tick_zero_current(void) {
    TEST("coulomb_tick() with zero current");
    coulomb_init_test(2200);
    mock_ina219_current_raw = 0;

    /* Simulate 100 ticks (100 ms) with no current */
    for (int i = 0; i < 100; i++) {
        coulomb_tick_test();
    }

    ASSERT_FLOAT(coulomb_get_coulombs_discharged_test(), 0.0f, 0.001f, "No coulombs discharged");
    ASSERT_FLOAT(coulomb_get_soc_test(), 100.0f, 0.1f, "SOC remains 100%");
    ASSERT(g_coulomb_state.tick_count == 100, "Tick count incremented");
}

void test_coulomb_tick_constant_discharge(void) {
    TEST("coulomb_tick() with constant 1A discharge");
    coulomb_init_test(2200);

    /* 1A = 10000 raw counts (at 0.0001 scale) */
    mock_ina219_current_raw = 10000;

    /* Simulate 3600 ticks (3.6 seconds, at 1kHz = 3.6 coulombs at 1A) */
    for (int i = 0; i < 3600; i++) {
        coulomb_tick_test();
    }

    float discharged = coulomb_get_coulombs_discharged_test();
    ASSERT_FLOAT(discharged, 3.6f, 0.1f, "1A for 3.6s = ~3.6 coulombs");

    float capacity_q = 2200.0f / 3.6f;  /* ~611 coulombs */
    float expected_soc = 100.0f * (1.0f - (3.6f / capacity_q));
    ASSERT_FLOAT(coulomb_get_soc_test(), expected_soc, 0.5f, "SOC decreases proportionally");
}

void test_charging_detection(void) {
    TEST("Charging vs. discharging detection");
    coulomb_init_test(2200);

    /* Negative current (charging): -1A = -10000 raw */
    mock_ina219_current_raw = -10000;
    coulomb_tick_test();
    ASSERT(g_coulomb_state.charging == true, "Negative current = charging");

    /* Positive current (discharging): +1A = +10000 raw */
    mock_ina219_current_raw = 10000;
    coulomb_tick_test();
    ASSERT(g_coulomb_state.charging == false, "Positive current = discharging");
}

void test_soc_calculation_accuracy(void) {
    TEST("SOC calculation accuracy");
    coulomb_init_test(2200);
    float capacity_q = BATTERY_CAPACITY_Q;  /* ~611 coulombs */

    /* Full discharge: 611 coulombs */
    mock_ina219_current_raw = 10000;  /* 1A */
    for (int i = 0; i < 611 * 3600; i++) {
        coulomb_tick_test();
    }

    ASSERT_FLOAT(coulomb_get_soc_test(), 0.0f, 1.0f, "Full discharge = 0% SOC");
    ASSERT(coulomb_get_soc_test() >= 0.0f && coulomb_get_soc_test() <= 100.0f, "SOC within bounds");
}

void test_soc_clamping(void) {
    TEST("SOC clamping to 0–100%");
    coulomb_init_test(2200);

    /* Manually set excessive discharge to test clamping */
    g_coulomb_state.coulombs_discharged = BATTERY_CAPACITY_Q + 100.0f;
    coulomb_tick_test();
    ASSERT(coulomb_get_soc_test() <= 0.0f, "SOC clamped to ≤0%");

    /* Manually set negative discharge */
    g_coulomb_state.coulombs_discharged = -100.0f;
    coulomb_tick_test();
    ASSERT(coulomb_get_soc_test() >= 100.0f, "SOC clamped to ≥100%");
}

void test_set_soc(void) {
    TEST("Manual SOC adjustment (coulomb_set_soc)");
    coulomb_init_test(2200);

    coulomb_set_soc_test(50.0f);
    ASSERT_FLOAT(coulomb_get_soc_test(), 50.0f, 0.1f, "SOC set to 50%");
    ASSERT_FLOAT(coulomb_get_coulombs_discharged_test(), BATTERY_CAPACITY_Q * 0.5f, 1.0f, "Coulombs adjusted");

    coulomb_set_soc_test(0.0f);
    ASSERT_FLOAT(coulomb_get_soc_test(), 0.0f, 0.1f, "SOC set to 0%");

    coulomb_set_soc_test(100.0f);
    ASSERT_FLOAT(coulomb_get_soc_test(), 100.0f, 0.1f, "SOC set to 100%");
}

void test_mark_full_charge(void) {
    TEST("Mark battery as fully charged");
    coulomb_init_test(2200);

    /* Simulate partial discharge */
    coulomb_set_soc_test(50.0f);
    ASSERT_FLOAT(coulomb_get_soc_test(), 50.0f, 0.1f, "Initial SOC = 50%");

    /* Mark as full */
    coulomb_mark_full_charge_test();
    ASSERT_FLOAT(coulomb_get_soc_test(), 100.0f, 0.1f, "SOC = 100% after mark_full");
    ASSERT_FLOAT(coulomb_get_coulombs_discharged_test(), 0.0f, 0.1f, "Discharged coulombs reset");
}

void test_mark_fully_discharged(void) {
    TEST("Mark battery as fully discharged");
    coulomb_init_test(2200);

    coulomb_set_soc_test(100.0f);
    uint16_t cycle_before = coulomb_get_cycle_count_test();

    coulomb_mark_fully_discharged_test();
    ASSERT_FLOAT(coulomb_get_soc_test(), 0.0f, 0.1f, "SOC = 0% after mark_discharged");
    ASSERT(coulomb_get_cycle_count_test() == (cycle_before + 1), "Cycle count incremented");
}

void test_flash_calibration_write_read(void) {
    TEST("Flash calibration write and read");
    coulomb_init_test(2200);

    g_calibration.magic = 0xCAFEBABE;
    g_calibration.current_offset_a = 0.05f;
    g_calibration.current_scale = 1.02f;
    g_calibration.total_cycles = 42;

    ASSERT(coulomb_save_calibration_test() == 0, "Calibration saved to flash");

    /* Clear runtime calibration */
    memset(&g_calibration, 0, sizeof(g_calibration));

    /* Reload from flash */
    ASSERT(coulomb_load_calibration_test() == 0, "Calibration loaded from flash");
    ASSERT_FLOAT(g_calibration.current_offset_a, 0.05f, 0.001f, "Offset preserved");
    ASSERT_FLOAT(g_calibration.current_scale, 1.02f, 0.001f, "Scale preserved");
    ASSERT(g_calibration.total_cycles == 42, "Cycle count preserved");
}

void test_flash_magic_validation(void) {
    TEST("Flash calibration magic checksum validation");
    coulomb_factory_reset_test();

    /* Write invalid magic to flash */
    coulomb_calibration_t bad_cal;
    bad_cal.magic = 0xDEADBEEF;  /* Invalid magic */
    bad_cal.current_offset_a = 0.1f;
    mock_flash_write(COULOMB_FLASH_ADDR, &bad_cal, sizeof(bad_cal));

    /* Try to load - should fail */
    int result = coulomb_load_calibration_test();
    ASSERT(result != 0, "Invalid magic rejected");
}

void test_calibration_offset_application(void) {
    TEST("Current offset calibration application");
    coulomb_init_test(2200);

    /* Set calibration offset */
    g_calibration.current_offset_a = 0.1f;  /* +100mA offset */
    g_calibration.current_scale = 1.0f;

    /* Read with offset: raw 0 + 0.1A offset = 0.1A actual */
    mock_ina219_current_raw = 0;
    coulomb_tick_test();
    ASSERT_FLOAT(coulomb_get_current_a_test(), 0.1f, 0.001f, "Offset applied to current");
}

void test_calibration_scale_application(void) {
    TEST("Current scale calibration application");
    coulomb_init_test(2200);

    g_calibration.current_offset_a = 0.0f;
    g_calibration.current_scale = 1.1f;  /* +10% scale */

    /* Raw 1A with 1.1x scale = 1.1A */
    mock_ina219_current_raw = 10000;  /* 1A */
    coulomb_tick_test();
    ASSERT_FLOAT(coulomb_get_current_a_test(), 1.1f, 0.01f, "Scale applied to current");
}

void test_factory_reset(void) {
    TEST("Factory reset clears all state");
    coulomb_init_test(2200);

    /* Corrupt state */
    g_coulomb_state.coulombs_discharged = 500.0f;
    g_coulomb_state.cycle_count = 42;
    g_calibration.current_offset_a = 0.5f;
    coulomb_save_calibration_test();

    /* Reset */
    coulomb_factory_reset_test();

    ASSERT(g_coulomb_state.coulombs_discharged == 0.0f, "Coulombs reset");
    ASSERT(g_coulomb_state.cycle_count == 0, "Cycle count reset");
    ASSERT_FLOAT(g_coulomb_state.soc_percent, 100.0f, 0.1f, "SOC reset to 100%");

    /* Verify flash erased */
    coulomb_calibration_t tmp;
    mock_flash_read(COULOMB_FLASH_ADDR, &tmp, sizeof(tmp));
    ASSERT(tmp.magic != 0xCAFEBABE, "Flash sector erased");
}

void test_capacity_variant(void) {
    TEST("Different battery capacities");
    coulomb_init_test(3000);  /* 3000 mAh variant */
    float capacity_q = 3000.0f / 3.6f;  /* ~833 coulombs */

    /* Discharge 1 coulomb and check SOC */
    mock_ina219_current_raw = 10000;  /* 1A */
    for (int i = 0; i < 3600; i++) {
        coulomb_tick_test();
    }

    float expected_soc = 100.0f * (1.0f - (1.0f / capacity_q));
    ASSERT_FLOAT(coulomb_get_soc_test(), expected_soc, 0.5f, "Capacity affects SOC calculation");
}

void test_low_current_threshold(void) {
    TEST("Low current threshold (50mA) for discharge detection");
    coulomb_init_test(2200);

    /* Current just below 50mA threshold (25mA) - should NOT count toward discharge */
    mock_ina219_current_raw = 250;  /* 0.025A = 25mA */
    for (int i = 0; i < 1000; i++) {
        coulomb_tick_test();
    }
    float discharged_below = coulomb_get_coulombs_discharged_test();
    ASSERT_FLOAT(discharged_below, 0.0f, 0.001f, "Below 50mA not counted as discharge");

    /* Reset and test above threshold */
    coulomb_init_test(2200);
    mock_ina219_current_raw = 600;  /* 0.06A = 60mA, above threshold */
    for (int i = 0; i < 1000; i++) {
        coulomb_tick_test();
    }
    float discharged_above = coulomb_get_coulombs_discharged_test();
    ASSERT_FLOAT(discharged_above, 0.06f, 0.01f, "Above 50mA counted as discharge");
}

void test_integration_over_long_duration(void) {
    TEST("Integration accuracy over extended discharge (10 seconds)");
    coulomb_init_test(2200);
    float capacity_q = BATTERY_CAPACITY_Q;

    /* Discharge at 0.5A for 10 seconds = 5 coulombs */
    mock_ina219_current_raw = 5000;  /* 0.5A */
    uint32_t ticks_per_10s = COULOMB_SAMPLE_RATE_HZ * 10;

    for (uint32_t i = 0; i < ticks_per_10s; i++) {
        coulomb_tick_test();
    }

    float discharged = coulomb_get_coulombs_discharged_test();
    ASSERT_FLOAT(discharged, 5.0f, 0.1f, "0.5A for 10s = 5 coulombs");

    float expected_soc = 100.0f * (1.0f - (5.0f / capacity_q));
    ASSERT_FLOAT(coulomb_get_soc_test(), expected_soc, 0.5f, "SOC accurate after extended discharge");
}

void test_discharge_then_charge(void) {
    TEST("Discharge then recharge cycle");
    coulomb_init_test(2200);

    /* Partial discharge (1A for 3.6 seconds = 3.6 coulombs) */
    mock_ina219_current_raw = 10000;
    for (int i = 0; i < COULOMB_SAMPLE_RATE_HZ * 3.6; i++) {
        coulomb_tick_test();
    }
    float soc_after_discharge = coulomb_get_soc_test();
    ASSERT_FLOAT(soc_after_discharge, 100.0f * (1.0f - (3.6f / BATTERY_CAPACITY_Q)), 0.5f, "SOC after discharge");

    /* Recharge (negative current: -1A) */
    mock_ina219_current_raw = -10000;
    for (int i = 0; i < 3600; i++) {
        coulomb_tick_test();
    }

    ASSERT(g_coulomb_state.charging == true, "Charging detected");
    /* Note: SOC doesn't automatically increase on negative current (only manual update via coulomb_set_soc) */
}

void test_tick_count_rollover(void) {
    TEST("Tick count increments correctly");
    coulomb_init_test(2200);

    ASSERT(g_coulomb_state.tick_count == 0, "Initial tick = 0");

    for (int i = 0; i < 100; i++) {
        coulomb_tick_test();
    }

    ASSERT(g_coulomb_state.tick_count == 100, "Tick count incremented to 100");

    /* Simulate run-time overflow near uint32_t max */
    g_coulomb_state.tick_count = 0xFFFFFFF0;  /* 4 billion ticks */
    coulomb_tick_test();
    ASSERT(g_coulomb_state.tick_count == 0xFFFFFFF1, "Tick count continues past large values");
}

/* ══════════════════════════════════════════════════════════════════════════ */
/* MAIN TEST RUNNER                                                           */
/* ══════════════════════════════════════════════════════════════════════════ */

int main(void) {
    printf("\n════════════════════════════════════════════════════════════════════════\n");
    printf("  Battery Coulomb Counter — Unit Tests (Issue #325)\n");
    printf("════════════════════════════════════════════════════════════════════════\n");

    test_initialization();
    test_coulomb_tick_zero_current();
    test_coulomb_tick_constant_discharge();
    test_charging_detection();
    test_soc_calculation_accuracy();
    test_soc_clamping();
    test_set_soc();
    test_mark_full_charge();
    test_mark_fully_discharged();
    test_flash_calibration_write_read();
    test_flash_magic_validation();
    test_calibration_offset_application();
    test_calibration_scale_application();
    test_factory_reset();
    test_capacity_variant();
    test_low_current_threshold();
    test_integration_over_long_duration();
    test_discharge_then_charge();
    test_tick_count_rollover();

    printf("\n────────────────────────────────────────────────────────────────────────\n");
    printf("  Results: %d/%d tests passed, %d failed\n", test_passed, test_count, test_failed);
    printf("────────────────────────────────────────────────────────────────────────\n\n");

    return (test_failed == 0) ? 0 : 1;
}