tests: drivers: uart: async_api: Align test to gcov

When CONFIG_COVERAGE is enabled then performance is degraded.
In that case higher baudrates shall be avoided because CPU may
not have enough time to handle UART interrupts. Limit baudrate
to 115200 when CONFIG_COVERAGE=y.

Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>

Author: nordic-krch

tests/drivers/uart/uart_async_api/src/test_uart_async.c

@@ -82,16 +82,23 @@ static void uart_async_test_init(int idx)
 	k_sem_reset(&rx_buf_released);
 	k_sem_reset(&rx_disabled);
 
-#ifdef CONFIG_UART_WIDE_DATA
-	const struct uart_config uart_cfg = {
-		.baudrate = 115200,
-		.parity = UART_CFG_PARITY_NONE,
-		.stop_bits = UART_CFG_STOP_BITS_1,
-		.data_bits = UART_CFG_DATA_BITS_9,
-		.flow_ctrl = UART_CFG_FLOW_CTRL_NONE
+	struct uart_config uart_cfg;
+
+	zassert_equal(uart_config_get(uart_dev, &uart_cfg), 0);
+
+	if (IS_ENABLED(CONFIG_COVERAGE)) {
+		/* When coverage is used then performance is degraded - avoid using
+		 * higher baudrates.
+		 */
+		uart_cfg.baudrate = MIN(uart_cfg.baudrate, 115200);
+	} else if (IS_ENABLED(CONFIG_UART_WIDE_DATA)) {
+		uart_cfg.baudrate = 115200;
+		uart_cfg.parity = UART_CFG_PARITY_NONE;
+		uart_cfg.stop_bits = UART_CFG_STOP_BITS_1;
+		uart_cfg.data_bits = UART_CFG_DATA_BITS_9;
+		uart_cfg.flow_ctrl = UART_CFG_FLOW_CTRL_NONE;
 	};
-	__ASSERT_NO_MSG(uart_configure(uart_dev, &uart_cfg) == 0);
-#endif
+	zassert_equal(uart_configure(uart_dev, &uart_cfg), 0);
 
 	if (!initialized) {
 		initialized = true;