fun <T : Throwable> Assert<T>.message(assertionCreator: Assert<String>.() -> Unit): UnitCreates an AssertionPlantNullable for the message of the plant's subject (which is a Throwable) and makes the assertion that message notToBeNull and uses assertionCreator which might create further Assertions which are lazily evaluated at the end.
AssertionError - Might throw an AssertionError in case message is null
or if an additionally created Assertions (by calling assertionCreator) does not hold.
Return
Notice, that this assertion function cannot provide a fluent API because it depends on whether the first
assertion message is not null) holds or not.
Define subsequent assertions via the assertionCreator lambda.