I tried to use Kotest with Spring, but I only foun...

# kotest

[hantsy]

I tried to use Kotest with Spring, but I only found the AnnotationSpec working well.

@Import(TestcontainersConfiguration::class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class DemoApplicationAnnotationSpec : AnnotationSpec() {
    @LocalServerPort
    private var port: Int = 8080
    lateinit var client: WebClient

    @BeforeEach
    fun setUp() {
        client = WebClient.create("<http://localhost>:$port")
    }

    @Test
    fun `get all posts`() {
        client.get()
            .uri("/posts")
            .accept(MediaType.APPLICATION_JSON)
            .exchangeToFlux {
                assertThat(it.statusCode()).isEqualTo(HttpStatus.OK)
                it.bodyToFlux(Post::class.java)
            }
            .test()
            .expectNextCount(2)
            .verifyComplete()
    }
}

How to convert this to use StringSpec FuncSpec ,etc., especially I do not know where to use the Spring special annotation to inject beans, such as LocalServerPort , MockkBean , etc.

I have tried to use LocalServerPort in the test class body, but it can not be accessed in the test block.

xxxStringSpec:StringSpec({
   //1. @LocalServerPort is NOT allowed here
   //2. The port injected in the class body(below) cannot be accessed here.

}){
    @LocalServerPort
    private var port: Int = 8080
}

[Emil Kantis]

Normally you would inject it in the constructor. With @MockkBean, you need to specify the annotation target as well, for instance:

class FooTest(
  @field:MockkBean val myMockService: Service
): StringSpec({
   // ...
})

[Emil Kantis]

I haven't used @LocalServerPort, but try adding it in the same place, and try around with different annotation targets until you figure out what's needed 🙂

[hantsy]

@Emil Kantis I know the constructor injection should work when registering SpringAutowireConstructorExtension, but here I have tried use @field:LocalServerPort var port: Int = 8080 in the top level class constructor, it does not work, it always return 8080 in the testing codes, which will fail the test running.

[Emil Kantis]

Can you share a repo w/ reproducer?

[hantsy]

The test is https://github.com/hantsy/spring-puzzles/blob/master/programming-models/webflux-kt[…]n/src/test/kotlin/com/example/demo/DemoApplicationSpringSpec.kt

And the project is a simple Spring project, https://github.com/hantsy/spring-puzzles/tree/master/programming-models/webflux-ktco-fn

[Emil Kantis]

It seems Spring mutates the @LocalServerPort field during runtime. You need to define it as a field rather than constructor parameter. Example:

@Import(TestcontainersConfiguration::class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class DemoApplicationFuncSpec : FunSpec() {
    @LocalServerPort
    var port: Int = 8080
    lateinit var client: WebClient

    init {

        beforeEach {
            client = WebClient.create("<http://localhost>:$port")
        }

        test("get all posts") {
            client.get()
                .uri("/posts")
                .accept(MediaType.APPLICATION_JSON)
                .exchangeToFlux {
                    assertThat(it.statusCode()).isEqualTo(HttpStatus.OK)
                    it.bodyToFlux(Post::class.java)
                }
                .test()
                .expectNextCount(2)
                .verifyComplete()
        }
    }
}

[Emil Kantis]

You can have it a constructor param as well, but when you use the short-form of defining specs, what ends up happening is that you capture the default value of the param for the entire spec, rather than looking up the field.

If you try adding any other field to an actual body, you can see that you can't actually access those fields from the lambda passed to the FunSpec constructor.

[Emil Kantis]

I.e this also works:

@Import(TestcontainersConfiguration::class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class DemoApplicationFuncSpec(
    @field:LocalServerPort var port: Int = 8080,
) : FunSpec() {
    init {
        lateinit var client: WebClient
        beforeEach {
            client = WebClient.create("<http://localhost>:$port")
        }

        test("get all posts") {
            client.get()
                .uri("/posts")
                .accept(MediaType.APPLICATION_JSON)
                .exchangeToFlux {
                    assertThat(it.statusCode()).isEqualTo(HttpStatus.OK)
                    it.bodyToFlux(Post::class.java)
                }
                .test()
                .expectNextCount(2)
                .verifyComplete()
        }
    }
}

[Emil Kantis]

But if you try to do this, you'll see that port is unresolved in the lambda:

@Import(TestcontainersConfiguration::class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class DemoApplicationFuncSpec : FunSpec(
    {
        lateinit var client: WebClient
        beforeEach {
            client = WebClient.create("<http://localhost>:$port")
        }

        test("get all posts") {
            client.get()
                .uri("/posts")
                .accept(MediaType.APPLICATION_JSON)
                .exchangeToFlux {
                    assertThat(it.statusCode()).isEqualTo(HttpStatus.OK)
                    it.bodyToFlux(Post::class.java)
                }
                .test()
                .expectNextCount(2)
                .verifyComplete()
        }
    }
) {
    @LocalServerPort
    var port: Int = 8080
}

[hantsy]

This style works

class DemoApplicationFuncSpec(
    @field:LocalServerPort var port: Int = 8080
) : FunSpec(){
    init {}}

[hantsy]

The last one I have tried before, not working. The port can not be accessed in testing codes.

[hantsy]

It seems Spring mutates the @LocalServerPort field during runtime. You need to define it as a field rather than constructor parameter

We use this annoation to get the runtime randam port number instead of the fixed initial number.

[Emil Kantis]

Yes, but it seems to not be intialized when we construct the spec, but probably made available later just before running the first test.. if you remove the default value you'll see there's no value available for construction

[hantsy]

@field:LocalServerPort var port: Int?

And restore the test FunTest({...}) and got the error:

tensions.ExtensionException$BeforeEachException: org.springframework.web.util.InvalidUrlException: Bad authority

	at io.kotest.engine.test.TestExtensions$beforeTestBeforeAnyBeforeContainer$errors$2$2.invoke(TestExtensions.kt:81)
	at io.kotest.engine.test.TestExtensions$beforeTestBeforeAnyBeforeContainer$errors$2$2.invoke(TestExtensions.kt:81)
	at io.kotest.common.ResultsKt.mapError(results.kt:17)
	at io.kotest.engine.test.TestExtensions.beforeTestBeforeAnyBeforeContainer-gIAlu-s(TestExtensions.kt:81)
	at io.kotest.engine.test.interceptors.LifecycleInterceptor.intercept(LifecycleInterceptor.kt:47)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invokeSuspend(TestCaseExecutor.kt:100)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invoke(TestCaseExecutor.kt)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invoke(TestCaseExecutor.kt)
	at io.kotest.engine.test.interceptors.TestCaseExtensionInterceptor$intercept$2.invokeSuspend(TestCaseExtensionInterceptor.kt:24)
	at io.kotest.engine.test.interceptors.TestCaseExtensionInterceptor$intercept$2.invoke(TestCaseExtensionInterceptor.kt)
	at io.kotest.engine.test.interceptors.TestCaseExtensionInterceptor$intercept$2.invoke(TestCaseExtensionInterceptor.kt)
	at io.kotest.engine.test.TestExtensions$intercept$execute$1$1$1.invokeSuspend(TestExtensions.kt:143)
	at io.kotest.engine.test.TestExtensions$intercept$execute$1$1$1.invoke(TestExtensions.kt)
	at io.kotest.engine.test.TestExtensions$intercept$execute$1$1$1.invoke(TestExtensions.kt)
	at io.kotest.extensions.spring.SpringTestExtension.intercept(SpringTestExtension.kt:73)
	at io.kotest.engine.test.TestExtensions$intercept$execute$1$1.invokeSuspend(TestExtensions.kt:140)
	at io.kotest.engine.test.TestExtensions$intercept$execute$1$1.invoke(TestExtensions.kt)
	at io.kotest.engine.test.TestExtensions$intercept$execute$1$1.invoke(TestExtensions.kt)
	at io.kotest.engine.test.TestExtensions$intercept$execute$1$1$1.invokeSuspend(TestExtensions.kt:143)
	at io.kotest.engine.test.TestExtensions$intercept$execute$1$1$1.invoke(TestExtensions.kt)
	at io.kotest.engine.test.TestExtensions$intercept$execute$1$1$1.invoke(TestExtensions.kt)
	at io.kotest.extensions.spring.SpringTestExtension.intercept(SpringTestExtension.kt:73)
	at io.kotest.engine.test.TestExtensions$intercept$execute$1$1.invokeSuspend(TestExtensions.kt:140)
	at io.kotest.engine.test.TestExtensions$intercept$execute$1$1.invoke(TestExtensions.kt)
	at io.kotest.engine.test.TestExtensions$intercept$execute$1$1.invoke(TestExtensions.kt)
	at io.kotest.engine.test.TestExtensions.intercept(TestExtensions.kt:148)
	at io.kotest.engine.test.interceptors.TestCaseExtensionInterceptor.intercept(TestCaseExtensionInterceptor.kt:24)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invokeSuspend(TestCaseExecutor.kt:100)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invoke(TestCaseExecutor.kt)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invoke(TestCaseExecutor.kt)
	at io.kotest.engine.test.interceptors.BeforeSpecListenerInterceptor$intercept$runTest$1$4$1.invokeSuspend(BeforeSpecListenerInterceptor.kt:50)
	at io.kotest.engine.test.interceptors.BeforeSpecListenerInterceptor$intercept$runTest$1$4$1.invoke(BeforeSpecListenerInterceptor.kt)
	at io.kotest.engine.test.interceptors.BeforeSpecListenerInterceptor$intercept$runTest$1$4$1.invoke(BeforeSpecListenerInterceptor.kt)
	at io.kotest.engine.test.interceptors.BeforeSpecListenerInterceptor.intercept(BeforeSpecListenerInterceptor.kt:60)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invokeSuspend(TestCaseExecutor.kt:100)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invoke(TestCaseExecutor.kt)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invoke(TestCaseExecutor.kt)
	at io.kotest.engine.test.interceptors.TestEnabledCheckInterceptor.intercept(TestEnabledCheckInterceptor.kt:31)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invokeSuspend(TestCaseExecutor.kt:100)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invoke(TestCaseExecutor.kt)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invoke(TestCaseExecutor.kt)
	at io.kotest.engine.test.interceptors.CoroutineErrorCollectorInterceptor$intercept$3.invokeSuspend(CoroutineErrorCollectorInterceptor.kt:34)
	at io.kotest.engine.test.interceptors.CoroutineErrorCollectorInterceptor$intercept$3.invoke(CoroutineErrorCollectorInterceptor.kt)
	at io.kotest.engine.test.interceptors.CoroutineErrorCollectorInterceptor$intercept$3.invoke(CoroutineErrorCollectorInterceptor.kt)
	at kotlinx.coroutines.intrinsics.UndispatchedKt.startUndispatchedOrReturn(Undispatched.kt:61)
	at kotlinx.coroutines.BuildersKt__Builders_commonKt.withContext(Builders.common.kt:163)
	at kotlinx.coroutines.BuildersKt.withContext(Unknown Source)
	at io.kotest.engine.test.interceptors.CoroutineErrorCollectorInterceptor.intercept(CoroutineErrorCollectorInterceptor.kt:33)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invokeSuspend(TestCaseExecutor.kt:100)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invoke(TestCaseExecutor.kt)
	at io.kotest.engine.test.TestCaseExecutor$execute$3$1.invoke(TestCaseExecutor.kt)
	at io.kotest.engine.test.interceptors.CoroutineDispatcherFactoryInterceptor$intercept$4.invokeSuspend(coroutineDispatcherFactoryInterceptor.kt:57)
	at io.kotest.engine.test.interceptors.CoroutineDispatcherFactoryInterceptor$intercept$4.invoke(coroutineDispatcherFactoryInterceptor.kt)
	at io.kotest.engine.test.interceptors.CoroutineDispatcherFactoryInterceptor$intercept$4.invoke(coroutineDispatcherFactoryInterceptor.kt)
	at io.kotest.engine.concurrency.FixedThreadCoroutineDispatcherFactory$withDispatcher$4.invokeSuspend(FixedThreadCoroutineDispatcherFactory.kt:59)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith$$$capture(ContinuationImpl.kt:33)
	at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt)
	at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:104)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
	at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: org.springframework.web.util.InvalidUrlException: Bad authority

[Emil Kantis]

If you print what port is used in beforeEach, what is actually used now?

[hantsy]

@Import(TestcontainersConfiguration::class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class DemoApplicationFuncSpec(
    @field:LocalServerPort var port: Int?
) : FunSpec({
    lateinit var client: WebClient

    beforeEach {
        println("beforeEach:::local server port:$port")
        client = WebClient.create("<http://localhost>:$port")
    }

    test("get all posts") {
        client.get()
            .uri("/posts")
            .accept(MediaType.APPLICATION_JSON)
            .exchangeToFlux {
                assertThat(it.statusCode()).isEqualTo(HttpStatus.OK)
                it.bodyToFlux(Post::class.java)
            }
            .test()
            .expectNextCount(2)
            .verifyComplete()
    }
})

Print null and failed.

@Import(TestcontainersConfiguration::class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class DemoApplicationFuncSpec(
    @field:LocalServerPort var port: Int?
) : FunSpec() {
    init {
        lateinit var client: WebClient

        beforeEach {
            println("beforeEach:::local server port:$port")
            client = WebClient.create("<http://localhost>:$port")
        }

        test("get all posts") {
            client.get()
                .uri("/posts")
                .accept(MediaType.APPLICATION_JSON)
                .exchangeToFlux {
                    assertThat(it.statusCode()).isEqualTo(HttpStatus.OK)
                    it.bodyToFlux(Post::class.java)
                }
                .test()
                .expectNextCount(2)
                .verifyComplete()
        }
    }
}

Print beforeEach:::local server port:53518 and worked well. Here we use

webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)

Need spring to assign a random port at test runtime.