Testing a Fragment with JUnit 5 works exactly like it does with JUnit 4: through the FragmentScenario API. Unlike Activity tests, there is no special extension for Fragment-based tests: If you want to launch a scenario for a Fragment, simply use the API directly:

class MyFragmentTest { @Test fun myTest() { val scenario = FragmentScenario.launch<MyFragment>() // Do something with the scenario here... } }