使用 mockito 进行模拟测试时如何解决 NullpointerException？答案

【问题标题】：How to solve NullpointerException while testing mocked using mockito?使用 mockito 进行模拟测试时如何解决 NullpointerException？
【发布时间】：2020-08-17 12:41:19
【问题描述】：

如何解决 NullpointerException nodeInfoList.map { it.legalIdentities.last().name } 在使用 mockito 进行模拟测试时 nodeInfoList 属于类型？

##待测试的服务代码##

 val nodeInfoList=dataService.proxy.networkMapSnapshot()
        val nodeNameList =nodeInfoList.map { it.legalIdentities.last().name }
        ownerMap.map {
            if(nodeNameList.contains(CordaX500Name.parse(it.value))) {
            ownerList.add(it.key)
             }
         }
        maintanenceMap.map {
            if(nodeNameList.contains(CordaX500Name.parse(it.value))) {
                maintainerList.add(it.key)
            }
        }
        response["ownerList"] = ownerList
        response["maintainerList"] = maintainerList
        return ResponseEntity.status(200).body(response)
    }

#我写的测试函数#

    @Test(timeout = 300000)
fun ` get drop down data Test`() {

    val cordaRPCOps = Mockito.mock(CordaRPCOps::class.java)
    val listNodeInfoMock = Mockito.mock(listOf<net.corda.core.node.NodeInfo>()::class.java)
    val singleMockNodeInfo = Mockito.mock(net.corda.core.node.NodeInfo::class.java)
    val x500Name = CordaX500Name.parse("O=Building Owner1,L=Tokyo,C=JP")
    val list500Mock2 = listOf(x500Name)

    Mockito.`when`(cordaDataService!!.proxy).thenReturn(cordaRPCOps)
    Mockito.`when`(cordaRPCOps.networkMapSnapshot()).thenReturn(listNodeInfoMock)
    Mockito.`when`(listNodeInfoMock.map { it.legalIdentities.last().name }).thenReturn(list500Mock2)

    Mockito.`when`(list500Mock2.contains(CordaX500Name.parse("O=Building Owner1,L=Tokyo,C=JP"))).thenReturn(true)
    val dropDownData = staticDataService!!.getDropDownData()
    println("dropDownData " + dropDownData)
}

【问题讨论】：

标签： java unit-testing kotlin mockito corda

【解决方案1】：

我认为这取决于您的测试目标，您是否希望该列表为空以及是否要对其进行测试。一般来说，有很多方法可以使用 Mockito 处理空列表，例如，您可以查看 other post，看看哪种方法最适合您的目的。

【讨论】：

【解决方案2】：

 fun ` list data Test`() {
    val x500Name = CordaX500Name.parse("O=Maintenance Operator1,L=Tokyo,C=JP")
    val partyMock = Mockito.mock(Party::class.java)

    Mockito.`when`(cordaDataService!!.proxy).thenReturn(proxyMock)
    Mockito.`when`(proxyMock!!.networkMapSnapshot()).thenReturn(listNodeInfoMock)

    Mockito.`when`(listNodeInfoMock!!.iterator()).thenReturn(nodeInfoIterator)
    Mockito.`when`(nodeInfoIterator!!.hasNext()).thenReturn(true,false)
    Mockito.`when`(nodeInfoIterator.next()).thenReturn(nodeInfoMock).thenReturn(nodeInfoMock2)

    Mockito.`when`(nodeInfoMock!!.legalIdentities ).thenReturn(listOf(partyMock))
    Mockito.`when`(nodeInfoMock.legalIdentities.last().name ).thenReturn(x500Name)
    Mockito.`when`(list500Mock2!!.contains(x500Name)).thenReturn(true)

}

像这样重写测试函数。 Nullpointer 异常已解决。将@Mock 用于此处使用的一些模拟对象。

@InjectMocks
private val staticDataService: StaticDataService? = null
@Mock
private val cordaDataService: CordaDataService? = null
@Mock
private val proxyMock: CordaRPCOps? = null
@Mock
private val listNodeInfoMock: List<NodeInfo>? = null

【讨论】：