What exactly is 3D Touch?
On supported iOS devices, one may access additional functionality by applying varying levels of pressure to the touchscreen.
Apps can respond by displaying a context menu (or supporting Peek and Pop) to show one item and display a drop down menu with specific actions.
On devices running iOS 13 and later, people can use the touch and hold gesture to open a context menu, regardless of whether the device supports 3D Touch. On 3D Touch devices, the gesture can reveal the context menu more quickly.
How does Phonecheck Test 3D-Touch?
Phonecheck checks for the physical hardware component of this feature in comparison to the software aspect of 3D touch only.
When the hardware component is defective it will fail (usually when LCD has been replaced). Apple will substitute the physical hardware version of 3D-Touch for the software version of 3D-Touch - making it seem as if it's still functional which it is, technically but not for physical standards.
Thus, the result is at the user's discretion - if they would like to sell the device as fully working.
However the software is letting the user know that the actual Hardware component internally is not working.
If you would like to review your test plan to ensure 3D Touch is being tested in the background, contact support: