lvgl/tests/README.md

# Tests for LVGL

The tests in the folder can be run locally and automatically by GitHub CI.

## Running locally

### Requirements (Linux)

Install requirements by:

```sh
scripts/install-prerequisites.sh
```

### Run test
1. Run all executable tests with `./tests/main.py test`.
2. Build all build-only tests with `./tests/main.py build`.
3. Clean prior test build, build all build-only tests,
   run executable tests, and generate code coverage
   report `./tests/main.py --clean --report build test`.

For full information on running tests run: `./tests/main.py --help`.

## Running automatically

GitHub's CI automatically runs these tests on pushes and pull requests to `master` and `releasev8.*` branches.

## Directory structure
- `src` Source files of the tests
    - `test_cases` The written tests,
    - `test_runners` Generated automatically from the files in `test_cases`.
    - other miscellaneous files and folders
- `ref_imgs` - Reference images for screenshot compare
- `report` - Coverage report. Generated if the `report` flag was passed to `./main.py`
- `unity` Source files of the test engine

## Add new tests

### Create new test file
New test needs to be added into the `src/test_cases` folder. The name of the files should look like `test_<name>.c`. The basic skeleton of a test file copy `_test_template.c`.

### Asserts
See the list of asserts [here](https://github.com/ThrowTheSwitch/Unity/blob/master/docs/UnityAssertionsReference.md).

There are some custom, LVGL specific asserts:
- `TEST_ASSERT_EQUAL_SCREENSHOT("image1.png")` Render the active screen and compare its content with an image in the `ref_imgs` folder.
If the compare fails `lvgl/test_screenshot_error.h` is created with the content of the frame buffer as an image.
To see the that image `#include "test_screenshot_error.h"` and call `test_screenshot_error_show();`.
- `TEST_ASSERT_EQUAL_COLOR(color1, color2)` Compare two colors.

### Adding new reference images
The reference images can be taken by copy-pasting the test code in to LVGL simulator and saving the screen.
LVGL needs to
- 800x480 resolution
- 32 bit color depth
- `LV_USE_PERF_MONITOR` and `LV_USE_MEM_MONITOR` disabled
- use the default theme, with the default color (don't set a theme manually)