diff --git a/tests/kernel/mbox/mbox_api/src/main.c b/tests/kernel/mbox/mbox_api/src/main.c
index f25564d81a6..a96d10a3b6e 100644
--- a/tests/kernel/mbox/mbox_api/src/main.c
+++ b/tests/kernel/mbox/mbox_api/src/main.c
@@ -18,13 +18,13 @@ extern void test_mbox_target_source_thread_block(void);
 void test_main(void *p1, void *p2, void *p3)
 {
 	ztest_test_suite(test_mbox_api,
-		ztest_unit_test(test_mbox_kinit),/*keep init first!*/
-		ztest_unit_test(test_mbox_kdefine),
-		ztest_unit_test(test_mbox_put_get_null),
-		ztest_unit_test(test_mbox_put_get_buffer),
-		ztest_unit_test(test_mbox_async_put_get_buffer),
-		ztest_unit_test(test_mbox_async_put_get_block),
-		ztest_unit_test(test_mbox_target_source_thread_buffer),
-		ztest_unit_test(test_mbox_target_source_thread_block));
+			 ztest_unit_test(test_mbox_kinit),/*keep init first!*/
+			 ztest_unit_test(test_mbox_kdefine),
+			 ztest_unit_test(test_mbox_put_get_null),
+			 ztest_unit_test(test_mbox_put_get_buffer),
+			 ztest_unit_test(test_mbox_async_put_get_buffer),
+			 ztest_unit_test(test_mbox_async_put_get_block),
+			 ztest_unit_test(test_mbox_target_source_thread_buffer),
+			 ztest_unit_test(test_mbox_target_source_thread_block));
 	ztest_run_test_suite(test_mbox_api);
 }
diff --git a/tests/kernel/mbox/mbox_api/src/test_mbox_api.c b/tests/kernel/mbox/mbox_api/src/test_mbox_api.c
index f9fd5ef5a54..aedb3c28e59 100644
--- a/tests/kernel/mbox/mbox_api/src/test_mbox_api.c
+++ b/tests/kernel/mbox/mbox_api/src/test_mbox_api.c
@@ -76,7 +76,7 @@ static void tmbox_put(struct k_mbox *pmbox)
 		k_mbox_put(pmbox, &mmsg, K_FOREVER);
 		break;
 	case PUT_GET_BUFFER:
-		/*fall through*/
+	/*fall through*/
 	case TARGET_SOURCE_THREAD_BUFFER:
 		/**TESTPOINT: mbox sync put buffer*/
 		mmsg.info = PUT_GET_BUFFER;
@@ -100,14 +100,14 @@ static void tmbox_put(struct k_mbox *pmbox)
 		k_sem_take(&sync_sema, K_FOREVER);
 		break;
 	case ASYNC_PUT_GET_BLOCK:
-		/*fall through*/
+	/*fall through*/
 	case TARGET_SOURCE_THREAD_BLOCK:
 		/**TESTPOINT: mbox async put mem block*/
 		mmsg.info = ASYNC_PUT_GET_BLOCK;
 		mmsg.size = MAIL_LEN;
 		mmsg.tx_data = NULL;
 		zassert_equal(k_mem_pool_alloc(&mpooltx, &mmsg.tx_block,
-			MAIL_LEN, K_NO_WAIT), 0, NULL);
+					       MAIL_LEN, K_NO_WAIT), 0, NULL);
 		memcpy(mmsg.tx_block.data, data[info_type], MAIL_LEN);
 		if (info_type == TARGET_SOURCE_THREAD_BLOCK) {
 			mmsg.tx_target_thread = receiver_tid;
@@ -136,14 +136,14 @@ static void tmbox_get(struct k_mbox *pmbox)
 		mmsg.rx_source_thread = K_ANY;
 		/*verify return value*/
 		zassert_true(k_mbox_get(pmbox, &mmsg, rxdata, K_FOREVER) == 0,
-			NULL);
+			     NULL);
 		/*verify .info*/
 		zassert_equal(mmsg.info, PUT_GET_NULL, NULL);
 		/*verify .size*/
 		zassert_equal(mmsg.size, 0, NULL);
 		break;
 	case PUT_GET_BUFFER:
-		/*fall through*/
+	/*fall through*/
 	case TARGET_SOURCE_THREAD_BUFFER:
 		/**TESTPOINT: mbox sync get buffer*/
 		mmsg.size = sizeof(rxdata);
@@ -153,27 +153,27 @@ static void tmbox_get(struct k_mbox *pmbox)
 			mmsg.rx_source_thread = K_ANY;
 		}
 		zassert_true(k_mbox_get(pmbox, &mmsg, rxdata, K_FOREVER) == 0,
-			NULL);
+			     NULL);
 		zassert_equal(mmsg.info, PUT_GET_BUFFER, NULL);
 		zassert_equal(mmsg.size, sizeof(data[info_type]), NULL);
 		/*verify rxdata*/
 		zassert_true(memcmp(rxdata, data[info_type], MAIL_LEN) == 0,
-			NULL);
+			     NULL);
 		break;
 	case ASYNC_PUT_GET_BUFFER:
 		/**TESTPOINT: mbox async get buffer*/
 		mmsg.size = sizeof(rxdata);
 		mmsg.rx_source_thread = K_ANY;
 		zassert_true(k_mbox_get(pmbox, &mmsg, NULL, K_FOREVER) == 0,
-			NULL);
+			     NULL);
 		zassert_equal(mmsg.info, ASYNC_PUT_GET_BUFFER, NULL);
 		zassert_equal(mmsg.size, sizeof(data[info_type]), NULL);
 		k_mbox_data_get(&mmsg, rxdata);
 		zassert_true(memcmp(rxdata, data[info_type], MAIL_LEN) == 0,
-			NULL);
+			     NULL);
 		break;
 	case ASYNC_PUT_GET_BLOCK:
-		/*fall through*/
+	/*fall through*/
 	case TARGET_SOURCE_THREAD_BLOCK:
 		/**TESTPOINT: mbox async get mem block*/
 		mmsg.size = MAIL_LEN;
@@ -183,14 +183,14 @@ static void tmbox_get(struct k_mbox *pmbox)
 			mmsg.rx_source_thread = K_ANY;
 		}
 		zassert_true(k_mbox_get(pmbox, &mmsg, NULL, K_FOREVER) == 0,
-			NULL);
+			     NULL);
 		zassert_true(k_mbox_data_block_get
-			(&mmsg, &mpoolrx, &rxblock, K_FOREVER) == 0, NULL);
+				     (&mmsg, &mpoolrx, &rxblock, K_FOREVER) == 0, NULL);
 		zassert_equal(mmsg.info, ASYNC_PUT_GET_BLOCK, NULL);
 		zassert_equal(mmsg.size, MAIL_LEN, NULL);
 		/*verify rxblock*/
 		zassert_true(memcmp(rxblock.data, data[info_type], MAIL_LEN)
-			== 0, NULL);
+			     == 0, NULL);
 		k_mem_pool_free(&rxblock);
 		break;
 	default:
@@ -214,8 +214,8 @@ static void tmbox(struct k_mbox *pmbox)
 	/**TESTPOINT: thread-thread data passing via mbox*/
 	sender_tid = k_current_get();
 	receiver_tid = k_thread_create(&tdata, tstack, STACK_SIZE,
-		tmbox_entry, pmbox, NULL, NULL,
-		K_PRIO_PREEMPT(0), 0, 0);
+				       tmbox_entry, pmbox, NULL, NULL,
+				       K_PRIO_PREEMPT(0), 0, 0);
 	tmbox_put(pmbox);
 	k_sem_take(&end_sema, K_FOREVER);