Mockito ".thenThrow" throws: "Checked exception is invalid for this method!"

Question

I'm in the process of writing an endpoint and web layer integration test, but I stuck to test the 404 Error.

The Endpoint:

@PreAuthorize("hasPermission('admin.faq')")
override fun getHelpById(helpId: Long): ResponseEntity<HelpDto> {

    return try {
        val help = helpService.getHelp(helpId)
        val helpDto = helpMapper.helpToHelpDto(help)
        ResponseEntity.ok(helpDto)
    } catch (exception: HelpNotFoundException) {
        ResponseEntity.notFound().build()
    }
}

The service

override fun getHelp(helpId: Long): Help {

    val optionalHelp = helpRepository.findById(helpId)

    if (optionalHelp.isEmpty) {
        throw HelpNotFoundException(helpId)
    }

    return optionalHelp.get()
}

The test so far

@Test
fun requestGetHelpByIdWithWrongHelpIdExpect404() {
    val uri = "/helps/{helpId}"

    val headers = HttpHeaders()
    headers.add("X-UserID", "1")
    headers.add("X-Permissions", "admin.faq")
    val request: HttpEntity<HttpHeaders> = HttpEntity(headers)

    val helpId: Long = 1
    val params = mapOf("helpId" to helpId)

    val builder = UriComponentsBuilder.fromUriString(uri)

    val uriWithParams = builder.buildAndExpand(params).toUri().toString()

    Mockito.`when`(helpService.getHelp(helpId)).thenThrow(HelpNotFoundException::class.java)

    val result = testRestTemplate.exchange(uriWithParams, HttpMethod.GET, request, HelpDto::class.java)

    println(result.statusCode)

    assert(result != null)
    assert(result.statusCode == HttpStatus.NOT_FOUND)
}

With this test I tried to test the case if the helpId cannot be found. To simulate that I mocked the helpService and want the method .getHelp to throw the Exception "HelpNotFound" (I know that mocking isn't so common in Integration Tests, but I had no clue how to solve it without)

My problem:

As mentioned in the title, the call Mockito.`when`(helpService.getHelp(helpId)).thenThrow(HelpNotFoundException::class.java) throws the following ecxeption

Checked exception is invalid for this method!
Invalid: online.minimuenchen.mmos.socialservice.exceptions.HelpNotFoundException

My guesses:

I asked a friend of mine which in pretty good with java, and he said I have to add "throws HelpNotFoundException()" to the Method Signature, but thats not necessary in kotlin right. So I thought maybe it would help to add the annotation "@Throws(HelpNotFoundException::class)".

Another guess of mine is that "HelpNotFoundException::class.java" should be something like "HelpNotFoundException()".

If I should send more Infos please say it.

Answer 1

My problem was that I put the annotation @Throws() just into the Service Impl and not into the Interface.