How to support wl_touch input? (when developing clients)

[Campbell Barton]

Hi, what are some ways to test "wl_touch" events?

- Is it possible to make track-pads use the wl_touch interface?
- Is there a way to emulate touch input using a mouse?
- If specific hardware is needed, any suggestions?

For context, recently a user reported a bug where touch events aren't 
supported (wl_touch), see: https://wayland-book.com/seat/touch.html

While it seems fairly straightforward to support, I don't think I have 
any hardware that uses this interface & buying a Wacom touch-screen just 
to add support for wl_touch seems excessive (I already have a touch-pad 
& wacom-tablet, even though both support "touch" it it seems neither 
active the wl_touch API).

Any suggestions for how to test that wl_touch support is working for 
application/toolkit developers?