Problem definition Recently I’ve come to a problem running my UI tests because of a DefinitionOverrideException. That’s an exception thrown by the Koin library when we have a duplicated definition for a particular type. The way we use Koin on Android is by starting the container in the onCreate() method of the Application class and loading the relevant modules into the container. Here is how it may look like:

Intro Although it should be very clear by now, testing is a very important part of the software development. Tests are, in a way, a construction around the software, which provides confidence for altering its structure (mostly to improve it) while being sure the behaviour stays the same. This article is focused mainly on the UI tests in an Android application. Traditionally, testing the UI was done by running a mocked backend on the same machine where the device/emulator is exercising the UI tests.