Make kotlinx-coroutines-test an MPP (Kotlin#2965)

Change the build scripts and the file layout so that
kotlinx-coroutines-test is built on all platforms.

Author: dkhalanskyjb

build.gradle

@@ -4,14 +4,13 @@
 
 import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
 import org.jetbrains.kotlin.konan.target.HostManager
-import org.gradle.util.VersionNumber
 import org.jetbrains.dokka.gradle.DokkaTaskPartial
-import org.jetbrains.dokka.gradle.DokkaMultiModuleTask
 
 apply plugin: 'jdk-convention'
-apply from: rootProject.file("gradle/opt-in.gradle")
 
 def coreModule = "kotlinx-coroutines-core"
+def testModule = "kotlinx-coroutines-test"
+def multiplatform = [coreModule, testModule]
 // Not applicable for Kotlin plugin
 def sourceless = ['kotlinx.coroutines', 'kotlinx-coroutines-bom', 'integration-testing']
 def internal = ['kotlinx.coroutines', 'benchmarks', 'integration-testing']
@@ -112,7 +111,7 @@ apiValidation {
     ignoredProjects += unpublished + ["kotlinx-coroutines-bom"]
     if (build_snapshot_train) {
         ignoredProjects.remove("example-frontend-js")
-        ignoredProjects.add("kotlinx-coroutines-core")
+        ignoredProjects.add(coreModule)
     }
     ignoredPackages += "kotlinx.coroutines.internal"
 }
@@ -133,13 +132,31 @@ allprojects {
 // Add dependency to core source sets. Core is configured in kx-core/build.gradle
 configure(subprojects.findAll { !sourceless.contains(it.name) && it.name != coreModule }) {
     evaluationDependsOn(":$coreModule")
-    def platform = PlatformKt.platformOf(it)
-    apply plugin: "kotlin-${platform}-conventions"
-    dependencies {
-        // See comment below for rationale, it will be replaced with "project" dependency
-        api project(":$coreModule")
-        // the only way IDEA can resolve test classes
-        testImplementation project(":$coreModule").kotlin.targets.jvm.compilations.test.output.allOutputs
+    if (it.name in multiplatform) {
+        apply plugin: "kotlin-multiplatform"
+        apply from: rootProject.file("gradle/compile-jvm-multiplatform.gradle")
+        apply from: rootProject.file("gradle/compile-common.gradle")
+
+        if (rootProject.ext["native_targets_enabled"] as Boolean) {
+            apply from: rootProject.file("gradle/compile-native-multiplatform.gradle")
+        }
+
+        apply from: rootProject.file("gradle/compile-js-multiplatform.gradle")
+        apply from: rootProject.file("gradle/publish-npm-js.gradle")
+        kotlin.sourceSets.commonMain.dependencies {
+            api project(":$coreModule")
+        }
+        kotlin.sourceSets.jvmTest.dependencies {
+            implementation project(":$coreModule").kotlin.targets.jvm.compilations.test.output.allOutputs
+        }
+    } else {
+        def platform = PlatformKt.platformOf(it)
+        apply plugin: "kotlin-${platform}-conventions"
+        dependencies {
+            api project(":$coreModule")
+            // the only way IDEA can resolve test classes
+            testImplementation project(":$coreModule").kotlin.targets.jvm.compilations.test.output.allOutputs
+        }
     }
 }
 
@@ -150,7 +167,7 @@ configure(subprojects.findAll { !sourceless.contains(it.name) }) {
 
     // Configure options for all Kotlin compilation tasks
     tasks.withType(org.jetbrains.kotlin.gradle.tasks.AbstractKotlinCompile).all {
-        kotlinOptions.freeCompilerArgs += optInAnnotations.collect { "-Xopt-in=" + it }
+        kotlinOptions.freeCompilerArgs += OptInPresetKt.optInAnnotations.collect { "-Xopt-in=" + it }
         kotlinOptions.freeCompilerArgs += "-progressive"
         // Disable KT-36770 for RxJava2 integration
         kotlinOptions.freeCompilerArgs += "-XXLanguage:-ProhibitUsingNullableTypeParameterAgainstNotNullAnnotated"
@@ -177,7 +194,7 @@ if (build_snapshot_train) {
     }
 
     println "Manifest of kotlin-compiler-embeddable.jar for coroutines"
-    configure(subprojects.findAll { it.name == "kotlinx-coroutines-core" }) {
+    configure(subprojects.findAll { it.name == coreModule }) {
         configurations.matching { it.name == "kotlinCompilerClasspath" }.all {
             resolvedConfiguration.getFiles().findAll { it.name.contains("kotlin-compiler-embeddable") }.each {
                 def manifest = zipTree(it).matching {
@@ -194,9 +211,8 @@ if (build_snapshot_train) {
 
 // Redefine source sets because we are not using 'kotlin/main/fqn' folder convention
 configure(subprojects.findAll {
-    !sourceless.contains(it.name) &&
+    !sourceless.contains(it.name) && !multiplatform.contains(it.name) &&
             it.name != "benchmarks" &&
-            it.name != coreModule &&
             it.name != "example-frontend-js"
 }) {
     // Pure JS and pure MPP doesn't have this notion and are configured separately
@@ -250,7 +266,7 @@ configure(subprojects.findAll { !unpublished.contains(it.name) }) {
     }
 
     List<String> jarTasks
-    if (it.name == "kotlinx-coroutines-core") {
+    if (it.name in multiplatform) {
         jarTasks = ["jvmJar", "metadataJar"]
     } else if (it.name == "kotlinx-coroutines-debug") {
         // We shadow debug module instead of just packaging it
@@ -324,12 +340,12 @@ allprojects { subProject ->
             .matching {
                 // Excluding substituted project itself because of circular dependencies, but still do it
                 // for "*Test*" configurations
-                subProject.name != "kotlinx-coroutines-core" || it.name.contains("Test")
+                subProject.name != coreModule || it.name.contains("Test")
             }
             .configureEach { conf ->
                 conf.resolutionStrategy.dependencySubstitution {
-                    substitute(module("org.jetbrains.kotlinx:kotlinx-coroutines-core"))
-                            .using(project(":kotlinx-coroutines-core"))
+                    substitute(module("org.jetbrains.kotlinx:$coreModule"))
+                            .using(project(":$coreModule"))
                             .because("Because Kotlin compiler embeddable leaks coroutines into the runtime classpath, " +
                                     "triggering all sort of incompatible class changes errors")
                 }

buildSrc/src/main/kotlin/OptInPreset.kt

@@ -0,0 +1,13 @@
+/*
+ * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+val optInAnnotations = listOf(
+    "kotlin.RequiresOptIn",
+    "kotlin.experimental.ExperimentalTypeInference",
+    "kotlin.ExperimentalMultiplatform",
+    "kotlinx.coroutines.DelicateCoroutinesApi",
+    "kotlinx.coroutines.ExperimentalCoroutinesApi",
+    "kotlinx.coroutines.ObsoleteCoroutinesApi",
+    "kotlinx.coroutines.InternalCoroutinesApi",
+    "kotlinx.coroutines.FlowPreview")

buildSrc/src/main/kotlin/SourceSets.kt

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+import org.jetbrains.kotlin.gradle.plugin.*
+
+fun KotlinSourceSet.configureMultiplatform() {
+    val srcDir = if (name.endsWith("Main")) "src" else "test"
+    val platform = name.dropLast(4)
+    kotlin.srcDir("$platform/$srcDir")
+    if (name == "jvmMain") {
+        resources.srcDir("$platform/resources")
+    } else if (name == "jvmTest") {
+        resources.srcDir("$platform/test-resources")
+    }
+    languageSettings {
+        optInAnnotations.forEach { optIn(it) }
+        progressiveMode = true
+    }
+}

gradle/dokka.gradle.kts

@@ -37,7 +37,7 @@ tasks.withType(DokkaTaskPartial::class).configureEach {
             packageListUrl.set(rootProject.projectDir.toPath().resolve("site/stdlib.package.list").toUri().toURL())
         }
 
-        if (project.name != "kotlinx-coroutines-core") {
+        if (project.name != "kotlinx-coroutines-core" && project.name != "kotlinx-coroutines-test") {
             dependsOn(project.configurations["compileClasspath"])
             doFirst {
                 // resolve classpath only during execution

gradle/opt-in.gradle

@@ -12,7 +12,7 @@ apply plugin: 'signing'
 
 // ------------- tasks
 
-def isMultiplatform = project.name == "kotlinx-coroutines-core"
+def isMultiplatform = project.name == "kotlinx-coroutines-core" || project.name == "kotlinx-coroutines-test"
 def isBom = project.name == "kotlinx-coroutines-bom"
 
 if (!isBom) {

gradle/publish.gradle

@@ -70,19 +70,8 @@ if (rootProject.ext.native_targets_enabled) {
  * because JMV-only projects depend on core, thus core should always be initialized before configuration.
  */
 kotlin {
-    configure(sourceSets) {
-        def srcDir = name.endsWith('Main') ? 'src' : 'test'
-        def platform = name[0..-5]
-        kotlin.srcDirs = ["$platform/$srcDir"]
-        if (name == "jvmMain") {
-            resources.srcDirs = ["$platform/resources"]
-        } else if (name == "jvmTest") {
-            resources.srcDirs = ["$platform/test-resources"]
-        }
-        languageSettings {
-            progressiveMode = true
-            optInAnnotations.each { useExperimentalAnnotation(it) }
-        }
+    sourceSets.forEach {
+        SourceSetsKt.configureMultiplatform(it)
     }
 
     configure(targets) {

kotlinx-coroutines-core/build.gradle

@@ -14,7 +14,7 @@ internal object Unconfined : CoroutineDispatcher() {
     override fun isDispatchNeeded(context: CoroutineContext): Boolean = false
 
     override fun dispatch(context: CoroutineContext, block: Runnable) {
-        // It can only be called by the "yield" function. See also code of "yield" function.
+        /** It can only be called by the [yield] function. See also code of [yield] function. */
         val yieldContext = context[YieldContext]
         if (yieldContext != null) {
             // report to "yield" that it is an unconfined dispatcher and don't call "block.run()"

kotlinx-coroutines-core/common/src/Unconfined.kt

@@ -260,7 +260,7 @@ public fun <T> Flow<T>.skip(count: Int): Flow<T> = noImpl()
 @Deprecated(
     level = DeprecationLevel.ERROR,
     message = "Flow analogue of 'forEach' is 'collect'",
-    replaceWith = ReplaceWith("collect(block)")
+    replaceWith = ReplaceWith("collect(action)")
 )
 public fun <T> Flow<T>.forEach(action: suspend (value: T) -> Unit): Unit = noImpl()
 

kotlinx-coroutines-core/common/src/flow/Migration.kt

@@ -36,7 +36,7 @@ public final class kotlinx/coroutines/test/TestCoroutineDispatcher : kotlinx/cor
 
 public final class kotlinx/coroutines/test/TestCoroutineExceptionHandler : kotlin/coroutines/AbstractCoroutineContextElement, kotlinx/coroutines/CoroutineExceptionHandler, kotlinx/coroutines/test/UncaughtExceptionCaptor {
 	public fun <init> ()V
-	public fun cleanupTestCoroutines ()V
+	public fun cleanupTestCoroutinesCaptor ()V
 	public fun getUncaughtExceptions ()Ljava/util/List;
 	public fun handleException (Lkotlin/coroutines/CoroutineContext;Ljava/lang/Throwable;)V
 }
@@ -56,12 +56,11 @@ public final class kotlinx/coroutines/test/TestDispatchers {
 }
 
 public abstract interface class kotlinx/coroutines/test/UncaughtExceptionCaptor {
-	public abstract fun cleanupTestCoroutines ()V
+	public abstract fun cleanupTestCoroutinesCaptor ()V
 	public abstract fun getUncaughtExceptions ()Ljava/util/List;
 }
 
 public final class kotlinx/coroutines/test/UncompletedCoroutinesError : java/lang/AssertionError {
-	public fun <init> (Ljava/lang/String;Ljava/lang/Throwable;)V
-	public synthetic fun <init> (Ljava/lang/String;Ljava/lang/Throwable;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Ljava/lang/String;)V
 }
 

kotlinx-coroutines-test/api/kotlinx-coroutines-test.api

@@ -2,6 +2,12 @@
  * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
  */
 
-dependencies {
-    implementation(project(":kotlinx-coroutines-debug"))
+val experimentalAnnotations = listOf(
+    "kotlin.Experimental",
+    "kotlinx.coroutines.ExperimentalCoroutinesApi",
+    "kotlinx.coroutines.InternalCoroutinesApi"
+)
+
+kotlin {
+    sourceSets.all { configureMultiplatform() }
 }

kotlinx-coroutines-test/build.gradle.kts

@@ -126,4 +126,4 @@ public interface DelayController {
  */
 // todo: maybe convert into non-public class in 1.3.0 (need use-cases for a public exception type)
 @ExperimentalCoroutinesApi // Since 1.2.1, tentatively till 1.3.0
-public class UncompletedCoroutinesError(message: String, cause: Throwable? = null): AssertionError(message, cause)
+public class UncompletedCoroutinesError(message: String): AssertionError(message)

kotlinx-coroutines-test/src/DelayController.kt renamed to kotlinx-coroutines-test/common/src/DelayController.kt

@@ -80,19 +80,16 @@ public fun TestCoroutineDispatcher.runBlockingTest(block: suspend TestCoroutineS
     runBlockingTest(this, block)
 
 private fun CoroutineContext.checkArguments(): Pair<CoroutineContext, DelayController> {
-    // TODO optimize it
-    val dispatcher = get(ContinuationInterceptor).run {
-        this?.let { require(this is DelayController) { "Dispatcher must implement DelayController: $this" } }
-        this ?: TestCoroutineDispatcher()
+    val dispatcher = when (val dispatcher = get(ContinuationInterceptor)) {
+        is DelayController -> dispatcher
+        null -> TestCoroutineDispatcher()
+        else -> throw IllegalArgumentException("Dispatcher must implement DelayController: $dispatcher")
     }
-
-    val exceptionHandler =  get(CoroutineExceptionHandler).run {
-        this?.let {
-            require(this is UncaughtExceptionCaptor) { "coroutineExceptionHandler must implement UncaughtExceptionCaptor: $this" }
-        }
-        this ?: TestCoroutineExceptionHandler()
+    val exceptionHandler = when (val handler = get(CoroutineExceptionHandler)) {
+        is UncaughtExceptionCaptor -> handler
+        null -> TestCoroutineExceptionHandler()
+        else -> throw IllegalArgumentException("coroutineExceptionHandler must implement UncaughtExceptionCaptor: $handler")
     }
-
     val job = get(Job) ?: SupervisorJob()
-    return Pair(this + dispatcher + exceptionHandler + job, dispatcher as DelayController)
+    return Pair(this + dispatcher + exceptionHandler + job, dispatcher)
 }

kotlinx-coroutines-test/src/TestBuilders.kt renamed to kotlinx-coroutines-test/common/src/TestBuilders.kt

@@ -8,6 +8,7 @@ import kotlinx.atomicfu.*
 import kotlinx.coroutines.*
 import kotlinx.coroutines.internal.*
 import kotlin.coroutines.*
+import kotlin.jvm.*
 import kotlin.math.*
 
 /**
@@ -67,11 +68,7 @@ public class TestCoroutineDispatcher: CoroutineDispatcher(), Delay, DelayControl
     /** @suppress */
     override fun invokeOnTimeout(timeMillis: Long, block: Runnable, context: CoroutineContext): DisposableHandle {
         val node = postDelayed(block, timeMillis)
-        return object : DisposableHandle {
-            override fun dispose() {
-                queue.remove(node)
-            }
-        }
+        return DisposableHandle { queue.remove(node) }
     }
 
     /** @suppress */

kotlinx-coroutines-test/src/TestCoroutineDispatcher.kt renamed to kotlinx-coroutines-test/common/src/TestCoroutineDispatcher.kt

@@ -5,6 +5,7 @@
 package kotlinx.coroutines.test
 
 import kotlinx.coroutines.*
+import kotlinx.coroutines.internal.*
 import kotlin.coroutines.*
 
 /**
@@ -16,7 +17,7 @@ public interface UncaughtExceptionCaptor {
      * List of uncaught coroutine exceptions.
      *
      * The returned list is a copy of the currently caught exceptions.
-     * During [cleanupTestCoroutines] the first element of this list is rethrown if it is not empty.
+     * During [cleanupTestCoroutinesCaptor] the first element of this list is rethrown if it is not empty.
      */
     public val uncaughtExceptions: List<Throwable>
 
@@ -28,7 +29,7 @@ public interface UncaughtExceptionCaptor {
      *
      * @throws Throwable the first uncaught exception, if there are any uncaught exceptions.
      */
-    public fun cleanupTestCoroutines()
+    public fun cleanupTestCoroutinesCaptor()
 }
 
 /**
@@ -39,21 +40,22 @@ public class TestCoroutineExceptionHandler :
     AbstractCoroutineContextElement(CoroutineExceptionHandler), UncaughtExceptionCaptor, CoroutineExceptionHandler
 {
     private val _exceptions = mutableListOf<Throwable>()
+    private val _lock = SynchronizedObject()
 
     /** @suppress **/
     override fun handleException(context: CoroutineContext, exception: Throwable) {
-        synchronized(_exceptions) {
+        synchronized(_lock) {
             _exceptions += exception
         }
     }
 
     /** @suppress **/
     override val uncaughtExceptions: List<Throwable>
-        get() = synchronized(_exceptions) { _exceptions.toList() }
+        get() = synchronized(_lock) { _exceptions.toList() }
 
     /** @suppress **/
-    override fun cleanupTestCoroutines() {
-        synchronized(_exceptions) {
+    override fun cleanupTestCoroutinesCaptor() {
+        synchronized(_lock) {
             val exception = _exceptions.firstOrNull() ?: return
             // log the rest
             _exceptions.drop(1).forEach { it.printStackTrace() }

kotlinx-coroutines-test/src/TestCoroutineExceptionHandler.kt renamed to kotlinx-coroutines-test/common/src/TestCoroutineExceptionHandler.kt

@@ -14,7 +14,7 @@ import kotlin.coroutines.*
 public interface TestCoroutineScope: CoroutineScope, UncaughtExceptionCaptor, DelayController {
     /**
      * Call after the test completes.
-     * Calls [UncaughtExceptionCaptor.cleanupTestCoroutines] and [DelayController.cleanupTestCoroutines].
+     * Calls [UncaughtExceptionCaptor.cleanupTestCoroutinesCaptor] and [DelayController.cleanupTestCoroutines].
      *
      * @throws Throwable the first uncaught exception, if there are any uncaught exceptions.
      * @throws UncompletedCoroutinesError if any pending tasks are active, however it will not throw for suspended
@@ -31,7 +31,7 @@ private class TestCoroutineScopeImpl (
     DelayController by coroutineContext.delayController
 {
     override fun cleanupTestCoroutines() {
-        coroutineContext.uncaughtExceptionCaptor.cleanupTestCoroutines()
+        coroutineContext.uncaughtExceptionCaptor.cleanupTestCoroutinesCaptor()
         coroutineContext.delayController.cleanupTestCoroutines()
     }
 }