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将Java Mockito测试转换为Kotlin

mockito kotlin java

Jan B. HDR · 技术社区 · 6 年前

Java 测试到 Kotlin

@Test
public void testSomething() {

    Mockito.when(parkIdMappingRepository.save(Mockito.any(ParkIdMapping.class))).thenAnswer(
        (Answer<ParkIdMapping>) invocation -> {
            ParkIdMapping mapping = invocation.getArgument(0);
            mapping.setId(100L);
            return mapping;
        }
    );
    ParkIdMapping mapping = parkIdMappingRepository.save(new ParkIdMapping("123"));

    assertEquals(new Long(100L), mapping.getId());

Intellij Idea到Kotlin的转换结果是:

@Test
public fun test_correctParkIdMappingGeneration() {

    Mockito.`when`(parkIdMappingRepository.save(Mockito.any(ParkIdMapping::class.java))).thenAnswer(
        { invocation -> // compiler error
            val mapping = invocation.getArgument(0)
            mapping.id = 100L
            mapping
        } as Answer<ParkIdMapping>
    )
    val mapping = parkIdMappingRepository.save(ParkIdMapping("123"))

    assertEquals(100L, mapping.id)
}

无法推断此参数的类型。请明确指定。

我试过像这样调整lambda

    Mockito.`when`(parkIdMappingRepository.save(Mockito.any(ParkIdMapping::class.java))).thenAnswer(
        { invocation: InvocationOnMock ->
            val mapping = invocation.getArgument(0) as ParkIdMapping
            mapping.id = 100L
            mapping
        } as Answer<ParkIdMapping>
    )

java.lang.ClassCastException: com.foobar.ParkIdGenerationServiceTest$test\u correctParkIdMappingGeneration$1不能强制转换为org.mockito.stubbing.Answer

org.mockito.exceptions.misusing.UnfinishedStubbingException: -&燃气轮机;在com.foobar.ParkIdGenerationServiceTest.testSomething(帕基德)enerationServiceTest.kt:92)

最初的目的是修改传递给 save repository 把它还给我。有什么办法吗?

1 回复 | 直到 6 年前

Jan B. HDR 6 年前

移动到 Answer<ParkIdMapping> getArgument

Mockito.any() 在它的验证函数中返回null,由于Kotlin null安全特性,mock抛出NPE。

这样地:

fun <T> any(): T {
    Mockito.any<T>()
    return uninitialized()
}

fun <T> uninitialized(): T = null as T

测试将是:

@Test
public fun test_correctParkIdMappingGeneration() {

    Mockito.`when`<ParkIdMapping>(parkIdMappingRepository.save(any())).thenAnswer(
        { invocation -> // compiler error
            val mapping = invocation.getArgument<ParkIdMapping>(0)
            mapping.id = 100L
            mapping
        }
    )
    val mapping = parkIdMappingRepository.save(ParkIdMapping("123"))

    assertEquals(100L, mapping.id)
}

关于Kotlin和Mockito interop的未来阅读: https://medium.com/@elye.project/befriending-kotlin-and-mockito-1c2e7b0ef791