Unit-Testing a Coffee Roaster with Android

The startup mikafi is developing a coffee bean roaster for restaurants and coffee shops. To deliver high quality hard- and firmware, the team at mikafi needs a tool to run automated tests against the device. Since some tests are expected to run for a long time, it is important that they can also be scheduled for execution over night.

We created an Android app for tablets that connects to the device via USB. The tests are written in a general purpose scripting language, giving the engineer maximum flexibility. After unsuccessful attempts at embedding Kotlin, Groovy or Python, we settled on JavaScript. Thanks to being such a widely used language, it was easy to find a well maintained runtime with Android support. Together with mikafi, we designed a set of APIs that allow scripts to interact with the device and verify its behavior. This includes many assertions commonly found in unit testing frameworks, as well as a more specialized API that verifies behavior over a period of time. The app pulls scripts from a Git repository and analyzes them locally, after which they can be executed manually or on a schedule.

Our app is going to be instrumental in driving development of the coffee roaster. With the sheer endless possibilities enabled by a scripting language and our APIs, the tool could also be used for maintenance and diagnostic purposes. Moreover, the app will support any future mikafi devices that use the same communication protocol.