# lv_test_helpers.h (/api/debugging/test/lv_test_helpers_h)
Functions [#functions]
lv_test_wait [#lv_test_wait]
Emulate a delay. It's not real delay, but it tricks LVGL to think that the required time has been elapsed. `lv_timer_handler` is called after each millisecond, meaning all the events will be fired inside this function. At the end the animations and display will be also updated.
```c title=" " lineNumbers=1
void lv_test_wait(uint32_t ms)
```
Parameters
| Name | Type | Description |
| ---- | --------------------------- | ---------------------------------- |
| `ms` | | the number of milliseconds to pass |
lv_test_fast_forward [#lv_test_fast_forward]
Emulates some time passing. Update the animations and the display only once at the end.
```c title=" " lineNumbers=1
void lv_test_fast_forward(uint32_t ms)
```
Parameters
| Name | Type | Description |
| ---- | --------------------------- | ---------------------------------- |
| `ms` | | the number of milliseconds to pass |
Macros [#macros]
LV_HEAP_CHECK [#lv_heap_check]
```c title=" " lineNumbers=1
#define LV_HEAP_CHECK(x) \
do {} while(0)
```
lv_test_get_free_mem [#lv_test_get_free_mem]
```c title=" " lineNumbers=1
#define lv_test_get_free_mem() \
(65536)
```
LV_TEST_WIDTH_TO_STRIDE [#lv_test_width_to_stride]
```c title=" " lineNumbers=1
#define LV_TEST_WIDTH_TO_STRIDE(w, px_size) \
((((w) * (px_size) + (LV_DRAW_BUF_STRIDE_ALIGN - 1)) / LV_DRAW_BUF_STRIDE_ALIGN) * LV_DRAW_BUF_STRIDE_ALIGN)
```
Dependencies [#dependencies]