使用runBlockingTest测试Kotlin协程报This job has not completed yet错误如何解决

问题背景 #

在Micronaut框架下开发Kotlin协程项目，引入kotlinx-coroutines-test库编写接口测试用例时，使用runBlockingTest封装测试逻辑会执行失败。

报错测试代码 #

@Test
fun `test GET all posts endpoint`() = runBlockingTest {
    val response = client.exchange("/posts", Array<Post>::class.java).awaitSingle()

    response.status shouldBe HttpStatus.OK
    response.body()!!.map { it.title }.forAny {
        it shouldContain "Micronaut"
    }
}

异常信息 #

java.lang.IllegalStateException: This job has not completed yet
    at kotlinx.coroutines.JobSupport.getCompletionExceptionOrNull(JobSupport.kt:1190)
    at kotlinx.coroutines.test.TestBuildersKt.runBlockingTest(TestBuilders.kt:53)
    at kotlinx.coroutines.test.TestBuildersKt.runBlockingTest$default(TestBuilders.kt:45)
    at com.example.ApplicationTest.test GET posts endpoint(ApplicationTest.kt:30)

临时可用写法 #

将runBlockingTest替换为普通runBlocking即可正常执行测试：

@Test
fun `test GET all posts endpoint`() {
    runBlocking {
        val response = client.exchange("/posts", Array<Post>::class.java).awaitSingle()

        response.status shouldBe HttpStatus.OK
        response.body()!!.map { it.title }.forAny {
            it shouldContain "Micronaut"
        }
    }
}

最终解决方案 #

该问题是kotlinx-coroutines-test旧版本的已知缺陷，修复方案如下：

• 将项目的Kotlin协程依赖版本升级到1.6.0-RC及以上
• 使用官方新提供的runTest方法替代已废弃的runBlockingTest编写协程测试用例，即可彻底解决该错误

内容的提问来源于stack exchange，提问作者Hantsy