How do get kotlintest to work with Spring?

Question

I'm trying to use kotlintest along with Spring (not Spring Boot, just the standard spring-test). I'm finding it very difficult to do. Any pointers as to what I am doing wrong? I am somewhat of a Kotlin newbie as well so I could very well not be doing something correctly.

This is what I've tried so far:

import io.kotlintest.matchers.shouldBe
import io.kotlintest.specs.BehaviorSpec

import org.junit.ClassRule
import org.junit.Rule

import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import org.springframework.test.context.ContextConfiguration
import org.springframework.test.context.junit4.rules.SpringClassRule
import org.springframework.test.context.junit4.rules.SpringMethodRule

open class SomeBean {
  open fun sayHello() = "Hello"
}

@Configuration
open class TestConfig {
  @Bean
  open fun someBean(): SomeBean = SomeBean()
}

@ContextConfiguration(classes = arrayOf(TestConfig::class))
open class MyTests(var someBean: SomeBean) : BehaviorSpec() {
  @Rule
  @JvmField
  val springMethodRule: SpringMethodRule = SpringMethodRule()

  companion object {
    @ClassRule
    @JvmField
    val SPRING_CLASS_RULE: SpringClassRule = SpringClassRule()
  }

  init {
    given("A test") {
      `when`("When my test happens") {
        val hello = someBean.sayHello()

        then("Hello should be valid") {
          hello shouldBe "Hello"
        }
      }
    }
  }
}

Output:

java.lang.InstantiationException: MyTests
    at java.lang.Class.newInstance(Class.java:427)
    at io.kotlintest.KTestJUnitRunner.<init>(KTestJUnitRunner.kt:13)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
    at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:33)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.runTestClass(JUnitTestClassExecuter.java:86)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.execute(JUnitTestClassExecuter.java:57)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassProcessor.processTestClass(JUnitTestClassProcessor.java:66)
    at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:32)
    at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)
    at com.sun.proxy.$Proxy1.processTestClass(Unknown Source)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:109)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:146)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:128)
    at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:404)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
    at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NoSuchMethodException: MyTests.<init>()
    at java.lang.Class.getConstructor0(Class.java:3082)
    at java.lang.Class.newInstance(Class.java:412)
    ... 40 more

Another try:

import io.kotlintest.matchers.shouldBe
import io.kotlintest.specs.BehaviorSpec

import org.junit.ClassRule
import org.junit.Rule

import org.springframework.beans.factory.annotation.Autowired
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import org.springframework.test.context.ContextConfiguration
import org.springframework.test.context.junit4.rules.SpringClassRule
import org.springframework.test.context.junit4.rules.SpringMethodRule

open class SomeBean {
  open fun sayHello() = "Hello"
}

@Configuration
open class TestConfig {
  @Bean
  open fun someBean(): SomeBean = SomeBean()
}

@ContextConfiguration(classes = arrayOf(TestConfig::class))
open class MyTests : BehaviorSpec() {
  @Rule
  @JvmField
  val springMethodRule: SpringMethodRule = SpringMethodRule()

  @Autowired
  lateinit var someBean: SomeBean

  companion object {
    @ClassRule
    @JvmField
    val SPRING_CLASS_RULE: SpringClassRule = SpringClassRule()
  }

  init {
    given("A test") {
      `when`("When my test happens") {
          val hello = someBean.sayHello()

      then("Hello should be valid") {
           hello shouldBe "Hello"
        }
      }
    }
  }
}

Output:

kotlin.UninitializedPropertyAccessException: lateinit property someBean has not been initialized
    at MyTests.getSomeBean(SpringTests.kt:31)
    at MyTests$1$1.invoke(SpringTests.kt:42)
    at MyTests$1$1.invoke(SpringTests.kt:25)
    at io.kotlintest.specs.BehaviorSpec$Given.when(BehaviorSpec.kt:27)
    at MyTests$1.invoke(SpringTests.kt:41)
    at MyTests$1.invoke(SpringTests.kt:25)
    at io.kotlintest.specs.BehaviorSpec.given(BehaviorSpec.kt:18)
    at MyTests.<init>(SpringTests.kt:40)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at java.lang.Class.newInstance(Class.java:442)
    at io.kotlintest.KTestJUnitRunner.<init>(KTestJUnitRunner.kt:13)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
    at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:33)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.runTestClass(JUnitTestClassExecuter.java:86)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.execute(JUnitTestClassExecuter.java:57)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassProcessor.processTestClass(JUnitTestClassProcessor.java:66)
    at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:32)
    at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)
    at com.sun.proxy.$Proxy1.processTestClass(Unknown Source)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:109)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:146)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:128)
    at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:404)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
    at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
    at java.lang.Thread.run(Thread.java:748)

This works, but then its not using kotlintest - its just using standard JUnit, which isn't what I want:

@ContextConfiguration(classes = arrayOf(TestConfig::class))
class Tests {
  @Rule 
  @JvmField
  val springMethodRule: SpringMethodRule = SpringMethodRule()

  @Autowired
  private lateinit var someBean: SomeBean

  companion object {
    @ClassRule
    @JvmField
    val SPRING_CLASS_RULE: SpringClassRule = SpringClassRule()
  }

  @Test
  fun runTest(): Unit {
    someBean.sayHello() shouldBe "Hello"
  }
}

Answer 1

Since KotlinTest 3.0.0 you can use the Spring extension listener. This will auto wire up the class if you annotate your test class with @ContextConfiguration.

For example:

@ContextConfiguration(classes = [(Components::class)])
class UserServiceTest : WordSpec() {

  override fun listeners() = listOf(SpringListener)

  @Autowired
  var service: UserService? = null

  init {
    "SpringListener" should {
      "have autowired the service" {
        service!!.repository.findUser().name shouldBe "system_user"
      }
    }
  }
} 

You must add the kotlintest-extensions-spring dependency to your build.

In the above code I added the SpringListener only to a single class but you can use it project wide by adding it to your ProjectConfig.

Full example is here: https://github.com/kotlintest/kotlintest/tree/master/kotlintest-samples/kotlintest-samples-spring