How to use EngineDiscoveryRequest.engineFilters method of io.kotest.runner.junit.platform.KotestJunitPlatformTestEngine class

1package io.kotest.runner.junit.platform2import io.kotest.core.config.ProjectConfiguration3import io.kotest.core.extensions.Extension4import io.kotest.core.filter.TestFilter5import io.kotest.core.spec.Spec6import io.kotest.engine.TestEngineLauncher7import io.kotest.engine.listener.PinnedSpecTestEngineListener8import io.kotest.engine.listener.ThreadSafeTestEngineListener9import io.kotest.framework.discovery.Discovery10import io.kotest.mpp.Logger11import io.kotest.runner.junit.platform.gradle.GradleClassMethodRegexTestFilter12import io.kotest.runner.junit.platform.gradle.GradlePostDiscoveryFilterExtractor13import org.junit.platform.engine.DiscoverySelector14import org.junit.platform.engine.EngineDiscoveryRequest15import org.junit.platform.engine.ExecutionRequest16import org.junit.platform.engine.TestEngine17import org.junit.platform.engine.TestExecutionResult18import org.junit.platform.engine.UniqueId19import org.junit.platform.engine.discovery.MethodSelector20import org.junit.platform.engine.discovery.UniqueIdSelector21import org.junit.platform.engine.support.descriptor.EngineDescriptor22import org.junit.platform.launcher.LauncherDiscoveryRequest23import java.util.*24import kotlin.reflect.KClass25/**26 * A Kotest implementation of a Junit Platform [TestEngine].27 */28class KotestJunitPlatformTestEngine : TestEngine {29   private val logger = Logger(KotestJunitPlatformTestEngine::class)30   companion object {31      const val EngineId = "kotest"32   }33   override fun getId(): String = EngineId34   override fun getGroupId(): Optional<String> = Optional.of("io.kotest")35   override fun execute(request: ExecutionRequest) {36      logger.log { Pair(null, "ExecutionRequest[${request::class.java.name}] [configurationParameters=${request.configurationParameters}; rootTestDescriptor=${request.rootTestDescriptor}]") }37      val root = request.rootTestDescriptor as KotestEngineDescriptor38      when (root.error) {39         null -> execute(request, root)40         else -> abortExecution(request, root.error)41      }42   }43   private fun abortExecution(request: ExecutionRequest, e: Throwable) {44      request.engineExecutionListener.executionStarted(request.rootTestDescriptor)45      request.engineExecutionListener.executionFinished(request.rootTestDescriptor, TestExecutionResult.failed(e))46   }47   private fun execute(request: ExecutionRequest, root: KotestEngineDescriptor) {48      val configuration = ProjectConfiguration()49      val listener = ThreadSafeTestEngineListener(50         PinnedSpecTestEngineListener(51            JUnitTestEngineListener(52               SynchronizedEngineExecutionListener(53                  request.engineExecutionListener54               ),55               root,56            )57         )58      )59      request.configurationParameters.get("kotest.extensions").orElseGet { "" }60         .split(',')61         .map { it.trim() }62         .filter { it.isNotBlank() }63         .map { Class.forName(it).newInstance() as Extension }64         .forEach { configuration.registry.add(it) }65      TestEngineLauncher(listener)66         .withConfiguration(configuration)67         .withExtensions(root.testFilters)68         .withClasses(root.classes)69         .launch()70   }71   /**72    * gradlew --tests rules:73    * Classname: adds classname selector and ClassMethodNameFilter post discovery filter74    * Classname.method: adds classname selector and ClassMethodNameFilter post discovery filter75    * org.Classname: doesn't seem to invoke the discover or execute methods.76    *77    * filter in gradle test block:78    * includeTestsMatching("*Test") - class selectors and ClassMethodNameFilter with pattern79    * includeTestsMatching("*Test") AND includeTestsMatching("org.gradle.internal.*") - class selectors and ClassMethodNameFilter with two patterns80    */81   override fun discover(82      request: EngineDiscoveryRequest,83      uniqueId: UniqueId,84   ): KotestEngineDescriptor {85      logger.log { Pair(null, "JUnit discovery request [uniqueId=$uniqueId]") }86      logger.log { Pair(null, request.string()) }87      // if we are excluded from the engines then we say goodnight according to junit rules88      val isKotest = request.engineFilters().all { it.toPredicate().test(this) }89      if (!isKotest)90         return KotestEngineDescriptor(uniqueId, emptyList(), emptyList(), emptyList(), null)91      val classMethodFilterRegexes = GradlePostDiscoveryFilterExtractor.extract(request.postFilters())92      val gradleClassMethodTestFilter = GradleClassMethodRegexTestFilter(classMethodFilterRegexes)93      // a method selector is passed by intellij to run just a single method inside a test file94      // this happens for example, when trying to run a junit test alongside kotest tests,95      // and kotest will then run all other tests.96      // Some other engines run tests via uniqueId selectors97      // therefore, the presence of a MethodSelector or a UniqueIdSelector means we must run no tests in KT.98      // if we get a uniqueid with kotest as engine we throw because that should never happen99      val allSelectors = request.getSelectorsByType(DiscoverySelector::class.java)100      val containsUnsupported = allSelectors.any {101         if (it is UniqueIdSelector)102            if (it.uniqueId.engineId.get() == EngineId)103               throw RuntimeException("Kotest does not allow running tests via uniqueId")104            else true105         else106            it is MethodSelector107      }108      val descriptor = if (!containsUnsupported) {109         val discovery = Discovery(emptyList())110         val result = discovery.discover(request.toKotestDiscoveryRequest())111         KotestEngineDescriptor(112            uniqueId,113            result.specs,114            result.scripts,115            listOf(gradleClassMethodTestFilter),116            result.error117         )118      } else {119         KotestEngineDescriptor(uniqueId, emptyList(), emptyList(), emptyList(), null)120      }121      logger.log { Pair(null, "JUnit discovery completed [descriptor=$descriptor]") }122      return descriptor123   }124}125class KotestEngineDescriptor(126   id: UniqueId,127   val classes: List<KClass<out Spec>>,128   val scripts: List<KClass<*>>,129   val testFilters: List<TestFilter>,130   val error: Throwable?, // an error during discovery131) : EngineDescriptor(id, "Kotest") {132   override fun mayRegisterTests(): Boolean = true133}134fun EngineDiscoveryRequest.engineFilters() = when (this) {135   is LauncherDiscoveryRequest -> engineFilters.toList()136   else -> emptyList()137}138fun EngineDiscoveryRequest.postFilters() = when (this) {139   is LauncherDiscoveryRequest -> postDiscoveryFilters.toList()140   else -> emptyList()141}...

1val engineDiscoveryRequest = EngineDiscoveryRequestBuilder.request().selectors(selectClass(EngineDiscoveryRequestTest::class.java)).build()2val engineDiscoveryRequestTest = KotestJunitPlatformTestEngine()3val engineFilters = engineDiscoveryRequestTest.engineFilters(engineDiscoveryRequest)4assertThat(engineFilters).isNotNull5assertThat(engineFilters).hasSize(1)6assertThat(engineFilters[0]).isInstanceOf(KotestEngineFilter::class.java)7}8}9}