Kotlin Mockito Tests Failing for Exception Handling

Question

I'm trying to write exception handling and tests for said handling in Kotlin, using Mockito. The tests are failing due to the exceptions not being thrown and I can't figure out why. It looks like they should be thrown and I'm stumped.

Here is a sample of the code in question.

private fun tryToDoTheThing(workItem: WorkItem, metrics: Metrics) {
    try {
        serviceFacade.doTheThing(workItem.accountId, workItem.name)
    } catch (ex: Exception) {
        handleException(ex, metrics, workItem)
    }
}

@Throws(DoTheThingFailedException::class)
private fun handleException(ex: Exception, metrics: Metrics, workItem: WorkItem) {
    var message: String
    when (ex) {

        is <other exception cases that are not valid for this question> -> {
            throwTheThingFailedException(message, metrics)
        }

        is RuntimeException -> {
            metrics.addCount(FAULT, 1)
            val cause = ex.cause
            message = "Received exception when attempting to to the thing " +
                    "name=[${workItem.name}], accountId=[${workItem.accountId}]"

            if (cause is HttpFailureException) {
                metrics.addProperty(EXCEPTION, cause!!::class.java.simpleName)
            } else {
                metrics.addProperty(EXCEPTION, ex::class.java.simpleName)
            }
            LOG.info(message)
            throw DoTheThingFailedException(message, ex)
        }
    }
}

@Throws(DoTheThingFailedException::class)
private fun throwAcknowledgeJobFailedException(message: String, metrics: Metrics) {
    LOG.info(message)
    metrics.addCount(ERROR, 1)
    throw DoTheThingFailedException(message)
}

And here is the test

@Test(expected = RuntimeException::class)
fun handleRuntimeException() {
    // given        
    val errorMessage = "Received exception when attempting to acknowledge name=[name], accountId=[accountId]"

    `when`(serviceFacade.doTheThing(any(), any())).thenThrow(RuntimeException())

    // when (this calls the item that does the thing)
    val runOneIteration = WorkDispatcher::class.java.getDeclaredMethod("runOneIteration")
    runOneIteration.invoke(workDispatcher)

    // then
    verify(metrics).addCount(FAULT, 1)
    verify(metrics).addProperty(EXCEPTION, "RuntimeException")
}

I have also tried variations of throwing the exception in this test, including

whenever(serviceFacade.doTheThing(any(), any())).doAnswer { throw RuntimeException(errorMessage) }

and

whenever(serviceFacade.doTheThing(any(), any())).doThrow(RuntimeException(errorMessage))

Even if I add a println statement that verifies the exception is a runtime exception, after the log message, the exception prints but it still gives me the following result:

[junit] Testcase: handleRuntimeException(com.abc.def.packageName.WorkDispatcherTest):   FAILED
[junit] Expected exception: java.lang.RuntimeException
[junit] junit.framework.AssertionFailedError: Expected exception: java.lang.RuntimeException