How to use instantiate method of io.kotest.core.extensions.ConstructorExtension class

Best Kotest code snippet using io.kotest.core.extensions.ConstructorExtension.instantiate

MicronautKotestExtension.kt

Source:MicronautKotestExtension.kt

...65    override suspend fun afterContainer(testCase: TestCase, result: TestResult) {66        contexts[testCase.spec.javaClass.name]?.afterInvocation(testCase)67    }68    @Suppress("UNCHECKED_CAST")69    override fun <T : Spec> instantiate(clazz: KClass<T>): Spec? {70        val constructor = clazz.primaryConstructor71        val testClass: Class<Any> = clazz.java as Class<Any>72        var micronautTestValue = testClass73                    .annotations74                    .filterIsInstance<MicronautTest>()75                    .map { micronautTest -> buildValueObject(micronautTest) }76                    .firstOrNull()77        return if (micronautTestValue == null) {78            null79        } else {80            val createBean = constructor != null && constructor.parameters.isNotEmpty()81            val context = MicronautKotestContext(testClass, micronautTestValue, createBean)82            contexts[testClass.name] = context83            if (createBean) {...

MicronautKotest5Extension.kt

Source:MicronautKotest5Extension.kt

...64    override suspend fun afterContainer(testCase: TestCase, result: TestResult) {65        contexts[testCase.spec.javaClass.name]?.afterInvocation(testCase)66    }67    @Suppress("UNCHECKED_CAST")68    override fun <T : Spec> instantiate(clazz: KClass<T>): Spec? {69        val constructor = clazz.primaryConstructor70        val testClass: Class<Any> = clazz.java as Class<Any>71        val micronautTestValue = testClass72                    .annotations73                    .filterIsInstance<MicronautTest>()74                    .map { micronautTest -> buildValueObject(micronautTest) }75                    .firstOrNull()76        return if (micronautTestValue == null) {77            null78        } else {79            val createBean = constructor != null && constructor.parameters.isNotEmpty()80            val context = MicronautKotest5Context(testClass, micronautTestValue, createBean)81            contexts[testClass.name] = context82            if (createBean) {...

RobolectricExtension.kt

Source:RobolectricExtension.kt

...29               builder.setSdk(sdk)30            }31         }.build()32   }33   override fun <T : Spec> instantiate(clazz: KClass<T>): Spec? {34      clazz.findAnnotation<RobolectricTest>() ?: return null35      return ContainedRobolectricRunner(clazz.getConfig())36         .sdkEnvironment.bootstrappedClass<Spec>(clazz.java).newInstance()37   }38   override suspend fun intercept(spec: Spec, execute: suspend (Spec) -> Unit) {39      spec::class.findAnnotation<RobolectricTest>() ?: return execute(spec)40      val containedRobolectricRunner = ContainedRobolectricRunner(spec::class.getConfig())41      beforeSpec(containedRobolectricRunner)42      execute(spec)43      afterSpec(containedRobolectricRunner)44   }45   private fun beforeSpec(containedRobolectricRunner: ContainedRobolectricRunner) {46      Thread.currentThread().contextClassLoader =47         containedRobolectricRunner.sdkEnvironment.robolectricClassLoader...

RobolectricTestCaseExtension.kt

Source:RobolectricTestCaseExtension.kt

...15 * https://github.com/kotest/kotest/blob/master/kotest-extensions/kotest-extensions-robolectric/src/jvmMain/kotlin/io/kotest/extensions/robolectric/RobolectricExtension.kt16 */17class RobolectricTestCaseExtension : ConstructorExtension, TestCaseExtension {18    private val containedRobolectricRunner = ContainedRobolectricRunner()19    override fun <T : Spec> instantiate(clazz: KClass<T>): Spec? {20        if (clazz.isNotRobolectricClass()) return null21        return containedRobolectricRunner.sdkEnvironment.bootstrappedClass<Spec>(clazz.java)22            .newInstance()23    }24    private fun <T : Spec> KClass<T>.isNotRobolectricClass() =25        findAnnotation<RobolectricTest>() == null26    override suspend fun intercept(27        testCase: TestCase,28        execute: suspend (TestCase) -> TestResult29    ): TestResult {30        if (testCase.spec::class.isNotRobolectricClass()) {31            return execute(testCase)32        }33        val containedRobolectricRunner = ContainedRobolectricRunner()...

instantiateSpec.kt

Source:instantiateSpec.kt

...4import io.kotest.core.extensions.PostInstantiationExtension5import io.kotest.core.spec.Spec6import kotlin.reflect.KClass7import kotlin.reflect.jvm.isAccessible8internal actual suspend fun instantiate(kclass: KClass<*>, registry: ExtensionRegistry): Result<Spec> {9   return createAndInitializeSpec(kclass as KClass<out Spec>, registry)10}11/**12 * Creates an instance of a [Spec] by delegating to [ConstructorExtension], with13 * a fallback to a reflection based zero-args constructor.14 *15 * If the [kclass] represents an object, then the singleton object instance will be returned.16 *17 * After creation any [PostInstantiationExtension]s will be invoked.18 */19suspend fun <T : Spec> createAndInitializeSpec(kclass: KClass<T>, registry: ExtensionRegistry): Result<Spec> {20   return when (val obj = kclass.objectInstance) {21      null -> runCatching {22         val initial: Spec? = null23         val spec = registry24            .all()25            .filterIsInstance<ConstructorExtension>()26            .fold(initial) { spec, ext -> spec ?: ext.instantiate(kclass) } ?: javaReflectNewInstance(kclass)27         registry28            .all()29            .filterIsInstance<PostInstantiationExtension>()30            .fold(spec) { acc, ext -> ext.instantiated(acc) }31      }32      else -> Result.success(obj)33   }.onSuccess { spec ->34      spec.globalExtensions().forEach { registry.add(it) }35   }36}37internal fun <T : Spec> javaReflectNewInstance(clazz: KClass<T>): Spec {38   try {39      val constructor = clazz.constructors.find { it.parameters.isEmpty() }40         ?: throw SpecInstantiationException(41            "Could not create instance of $clazz. Specs must have a public zero-arg constructor.",42            null43         )44      constructor.isAccessible = true...

RobolectricSpecExtension.kt

Source:RobolectricSpecExtension.kt

...11 * https://github.com/kotest/kotest/blob/master/kotest-extensions/kotest-extensions-robolectric/src/jvmMain/kotlin/io/kotest/extensions/robolectric/RobolectricExtension.kt12 */13class RobolectricSpecExtension : ConstructorExtension, SpecExtension {14    private val containedRobolectricRunner = ContainedRobolectricRunner()15    override fun <T : Spec> instantiate(clazz: KClass<T>): Spec? {16        if (clazz.isNotRobolectricClass()) return null17        return containedRobolectricRunner.sdkEnvironment.bootstrappedClass<Spec>(clazz.java)18            .newInstance()19    }20    private fun <T : Spec> KClass<T>.isNotRobolectricClass() =21        findAnnotation<RobolectricTest>() == null22    override suspend fun intercept(spec: KClass<out Spec>, process: suspend () -> Unit) {23        if (spec.isNotRobolectricClass()) {24            process()25            return26        }27        val containedRobolectricRunner = ContainedRobolectricRunner()28        beforeTest(containedRobolectricRunner)29        process()...

SpringAutowireConstructorExtension.kt

Source:SpringAutowireConstructorExtension.kt

...6import org.springframework.test.context.TestContextManager7import kotlin.reflect.KClass8import kotlin.reflect.full.primaryConstructor9/**10 * A [ConstructorExtension] which will attempt to instantiate test classes if they have a11 * non-zero arg constructor.12 *13 * The extension will delegate to spring's [TestContextManager] to autowire the constructors.14 */15@AutoScan16object SpringAutowireConstructorExtension : ConstructorExtension {17   override fun <T : Spec> instantiate(clazz: KClass<T>): Spec? {18      // we only instantiate via spring if there's actually parameters in the constructor19      // otherwise there's nothing to inject there20      val constructor = clazz.primaryConstructor21      return if (constructor == null || constructor.parameters.isEmpty()) {22         null23      } else {24         val manager = TestContextManager(clazz.java)25         val context = manager.testContext.applicationContext26         context.autowireCapableBeanFactory.autowire(27            clazz.java,28            AutowireCapableBeanFactory.AUTOWIRE_CONSTRUCTOR, true29         ) as Spec30      }31   }32}...

ConstructorExtensionTest.kt

Source:ConstructorExtensionTest.kt

...24      test("a") {}25   }26}27private class ErroringConstructorExtension : ConstructorExtension {28   override fun <T : Spec> instantiate(clazz: KClass<T>): Spec? {29      error("THWACK!")30   }31}...

instantiate

Using AI Code Generation

1   val constructorExtension = ConstructorExtension()2   val instance = constructorExtension.instantiate(testCase)3   val invokeExtension = InvokeExtension()4   val result = invokeExtension.invoke(testCase, instance)5   val finalizeExtension = FinalizeExtension()6   val finalResult = finalizeExtension.finalize(testCase, result)7   finalResult shouldBe TestResult.success(1)8}

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