[nrf fromlist] tests: drivers: can: api: Validate CAN statistics

Extend CAN stats test. Add validation of returned data.
Assume that current value of error counters is smaller than
arbitrary threshold.

This is to detect bug in CAN driver implementation where
CAN stats are not correctly initialized.

Upstream PR #: 99796

Signed-off-by: Sebastian Głąb <[email protected]>

Author: nordic-segl

tests/drivers/can/api/src/stats.c

@@ -9,6 +9,9 @@
 
 #include "common.h"
 
+/* Arbitrary threshold */
+#define THRESHOLD  10
+
 /**
  * @addtogroup t_driver_can
  * @{
@@ -24,13 +27,21 @@ ZTEST_USER(can_stats, test_can_stats_accessors)
 	uint32_t val;
 
 	val = can_stats_get_bit_errors(can_dev);
+	zassert_true(val < THRESHOLD, "CAN bit errors are too high");
 	val = can_stats_get_bit0_errors(can_dev);
+	zassert_true(val < THRESHOLD, "CAN bit0 errors are too high");
 	val = can_stats_get_bit1_errors(can_dev);
+	zassert_true(val < THRESHOLD, "CAN bit1 errors are too high");
 	val = can_stats_get_stuff_errors(can_dev);
+	zassert_true(val < THRESHOLD, "CAN stuff errors are too high");
 	val = can_stats_get_crc_errors(can_dev);
+	zassert_true(val < THRESHOLD, "CAN crc errors are too high");
 	val = can_stats_get_form_errors(can_dev);
+	zassert_true(val < THRESHOLD, "CAN form errors are too high");
 	val = can_stats_get_ack_errors(can_dev);
+	zassert_true(val < THRESHOLD, "CAN ack errors are too high");
 	val = can_stats_get_rx_overruns(can_dev);
+	zassert_true(val < THRESHOLD, "CAN rx overruns are too high");
 }
 
 void *can_stats_setup(void)