kotlin-test's assertNotNull lets the compiler know...

# announcements

[Daniel Svensson]

kotlin-test's assertNotNull lets the compiler know that whatever is passed to it is not null afterwards, while junit's assertNotNull does not. Why is it like that?

[christophsturm]

its probably using contracts. look here https://kotlinlang.org/docs/reference/whatsnew13.html

[Petter Måhlén]

yes

/** Asserts that the [actual] value is not `null`, with an optional [message]. */
fun <T : Any> assertNotNull(actual: T?, message: String? = null): T {
    contract { returns() implies (actual != null) }
    asserter.assertNotNull(message, actual)
    return actual!!
}

[Daniel Svensson]

Thanks a lot guys!

[Daniel Svensson]

ah and look at that, https://github.com/junit-team/junit5/issues/1866