Mockito的argThat在Kotlin中返回null [英] Mockito's argThat returning null when in Kotlin

问题描述

给出以下课程(用kotlin编写):

Given the following class (written in kotlin):

class Target {
     fun <R> target(filter: String, mapper: (String) -> R): R = mapper(filter)
}

我能够在Java中测试代码:

I'm able to test in java, the test code:

@Test
public void testInJava() {
    Target mockTarget = Mockito.mock(Target.class);
    Mockito.when(mockTarget.target(
            argThat(it -> true),
            Mockito.argThat(it -> true)
    )).thenReturn(100);
    assert mockTarget.target("Hello World", it -> 1) == 100;
}

Java测试通过了预期的结果，但相同的测试用kotlin编写:

The java test pass as expected, but the same test is written in kotlin:

@Test
fun test() {
    val mockTarget = Mockito.mock(Target::class.java)
    Mockito.`when`(mockTarget.target(
            Mockito.argThat<String> { true },
            mapper = Mockito.argThat<Function1<String, Int>>({ true }))
    ).thenReturn(100)
    assert(mockTarget.target("Hello World") { 1 } == 100)
}

kotlin版本收到以下异常:

The kotlin version I receive the following exception:

java.lang.IllegalStateException: Mockito.argThat<String> { true } must not be null

为什么会发生这种情况，如何使用Kotlin进行测试?

Why is it happening and how can I test that using kotlin?

推荐答案

截至撰写本文时，mockito-kotlin的更新时间尚未超过一年.与所有这些库一样，始终需要不断更新它们，而我也不想卡在一个未维护的库中.

As of this writing, mockito-kotlin hasn't been updated for more than a year. As with all of these libraries, there's always a constant need for keeping them up-to-date, and I didn't want to get stuck with an unmaintained library.

所以我想出了另一种方法来解决argThat的null问题，而无需使用任何其他库.

So I came up with another way to solve the null issue with argThat without using any other libraries.

假设我们有一个界面UuidRepository，如下所示:

Say we've an interface UuidRepository as follows:

interface UuidRepository {
    suspend fun Entity save(entity: Entity): Entity
}

类Entity具有两个属性，userId: String和uuid: String.

以下代码失败:

Mockito.verify(uuidRepository).save(argThat { it.userId == someValue && it.uuid == "test" })

出现错误:

argThat {it.userId == someValue&& it.uuid =="test"； }不能为空

argThat { it.userId == someValue && it.uuid == "test" } must not be null

要解决此问题，我们在模拟中获得所有调用，然后验证所需的调用:

To solve this, we get all the invocation on the mock and then verify the ones we want:

val invocations = Mockito.mockingDetails(uuidRepository).invocations
    .filter { setOf("findById", "save").contains(it.method.name) }
    .map { it.method.name to it.arguments }
    .toMap()

assertThat(invocations).containsKey("save")
val first = invocations["save"]?.first()
assertThat(first).isNotNull
val entity = first as Entity
assertThat(entity.userId).isEqualTo(someValue)
assertThat(entity.uuid).isEqualTo("test")

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