fix(gps): make acquisition and reacquisition deterministic

soc/software/gps_system/tests/test_gps_acq_manager.c

@@ -0,0 +1,144 @@
+#include <assert.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+#include "gps/gps_acq_manager.h"
+
+static gps_acq_manager_t make_manager(
+	uint64_t retry_delay,
+	uint64_t hot_retry_delay,
+	uint64_t hot_window,
+	unsigned int max_hot_streak)
+{
+	gps_acq_manager_t manager;
+	const gps_acq_manager_config_t config = {
+		.retry_delay_ticks = retry_delay,
+		.hot_retry_delay_ticks = hot_retry_delay,
+		.hot_window_ticks = hot_window,
+		.max_hot_streak = max_hot_streak
+	};
+	gps_acq_manager_init(&manager, &config);
+	return manager;
+}
+
+static unsigned int start_next(
+	gps_acq_manager_t* manager,
+	uint64_t now,
+	bool expected_hot)
+{
+	unsigned int prn = GPS_ACQ_MANAGER_INVALID_PRN;
+	bool hot = !expected_hot;
+	assert(gps_acq_manager_start_next(manager, now, &prn, &hot));
+	assert(hot == expected_hot);
+	return prn;
+}
+
+static void test_cold_round_robin_and_retry_from_tick_zero(void)
+{
+	gps_acq_manager_t manager =
+		make_manager(5u, 5u, 100u, 4u);
+	assert(gps_acq_manager_enable_cold(&manager, 0u));
+	assert(gps_acq_manager_enable_cold(&manager, 1u));
+	assert(gps_acq_manager_enable_cold(&manager, 2u));
+
+	assert(start_next(&manager, 0u, false) == 0u);
+	/* A tick-zero attempt is real and must still observe retry delay. */
+	gps_acq_manager_mark_failed(&manager, 0u, 0u);
+	assert(start_next(&manager, 0u, false) == 1u);
+	gps_acq_manager_mark_failed(&manager, 1u, 0u);
+	assert(start_next(&manager, 0u, false) == 2u);
+	gps_acq_manager_mark_failed(&manager, 2u, 0u);
+
+	unsigned int ignored;
+	assert(!gps_acq_manager_start_next(
+		&manager, 4u, &ignored, NULL));
+	assert(start_next(&manager, 5u, false) == 0u);
+}
+
+static void test_hot_priority_round_robin_and_cold_fairness(void)
+{
+	gps_acq_manager_t manager =
+		make_manager(1u, 1u, 100u, 2u);
+	assert(gps_acq_manager_enable_cold(&manager, 0u));
+	assert(gps_acq_manager_enable_cold(&manager, 1u));
+	gps_acq_manager_mark_lost(&manager, 7u, 10u);
+	gps_acq_manager_mark_lost(&manager, 8u, 10u);
+
+	assert(start_next(&manager, 10u, true) == 7u);
+	gps_acq_manager_mark_failed(&manager, 7u, 11u);
+	assert(start_next(&manager, 11u, true) == 8u);
+	gps_acq_manager_mark_failed(&manager, 8u, 12u);
+
+	/* Two hot attempts force one cold discovery attempt. */
+	assert(start_next(&manager, 12u, false) == 0u);
+	gps_acq_manager_mark_failed(&manager, 0u, 13u);
+	assert(start_next(&manager, 13u, true) == 7u);
+}
+
+static void test_expired_hot_becomes_cold_and_tracking_is_excluded(void)
+{
+	gps_acq_manager_t manager =
+		make_manager(1u, 1u, 10u, 4u);
+	assert(gps_acq_manager_enable_cold(&manager, 2u));
+	gps_acq_manager_mark_lost(&manager, 9u, 20u);
+
+	unsigned int prn = start_next(&manager, 31u, false);
+	assert(prn == 2u);
+	gps_acq_manager_mark_tracking(&manager, prn);
+
+	prn = start_next(&manager, 31u, false);
+	assert(prn == 9u);
+	gps_acq_manager_mark_acquired(&manager, prn);
+	unsigned int ignored;
+	assert(!gps_acq_manager_start_next(
+		&manager, 100u, &ignored, NULL));
+
+	gps_acq_manager_mark_tracking(&manager, 9u);
+	gps_acq_manager_mark_stale(&manager, 9u);
+	assert(gps_acq_manager_state(&manager, 9u) ==
+	       GPS_ACQ_PRN_STALE);
+	gps_acq_manager_mark_lost(&manager, 9u, 101u);
+	assert(gps_acq_manager_state(&manager, 9u) ==
+	       GPS_ACQ_PRN_HOT);
+}
+
+static void test_invalid_inputs_are_safe(void)
+{
+	gps_acq_manager_t manager =
+		make_manager(1u, 1u, 10u, 0u);
+	assert(!gps_acq_manager_enable_cold(
+		&manager, GPS_ACQ_MANAGER_PRN_COUNT));
+	assert(gps_acq_manager_state(
+		&manager, GPS_ACQ_MANAGER_PRN_COUNT) ==
+	       GPS_ACQ_PRN_DISABLED);
+	assert(!gps_acq_manager_start_next(NULL, 0u, NULL, NULL));
+	assert(gps_acq_manager_count_searchable(NULL) == 0u);
+}
+
+static void test_failed_hot_search_is_backed_off(void)
+{
+	gps_acq_manager_t manager =
+		make_manager(1u, 30u, 100u, 4u);
+	assert(gps_acq_manager_enable_cold(&manager, 0u));
+	gps_acq_manager_mark_lost(&manager, 20u, 0u);
+
+	assert(start_next(&manager, 0u, true) == 20u);
+	gps_acq_manager_mark_failed(&manager, 20u, 5u);
+	assert(start_next(&manager, 5u, false) == 0u);
+	gps_acq_manager_mark_failed(&manager, 0u, 6u);
+	assert(start_next(&manager, 7u, false) == 0u);
+	gps_acq_manager_mark_failed(&manager, 0u, 8u);
+
+	assert(start_next(&manager, 35u, true) == 20u);
+}
+
+int main(void)
+{
+	test_cold_round_robin_and_retry_from_tick_zero();
+	test_hot_priority_round_robin_and_cold_fairness();
+	test_expired_hot_becomes_cold_and_tracking_is_excluded();
+	test_invalid_inputs_are_safe();
+	test_failed_hot_search_is_backed_off();
+	puts("gps acquisition manager tests passed");
+	return 0;
+}