Tweak Kover: improve coverage, disable deprecations, add missing test…

buildSrc/src/main/kotlin/kover-conventions.gradle.kts

@@ -10,16 +10,12 @@ val notCovered = sourceless + internal + unpublished
 
 val expectedCoverage = mutableMapOf(
     // These have lower coverage in general, it can be eventually fixed
-    "kotlinx-coroutines-swing" to 70,
-    "kotlinx-coroutines-android" to 50,
+    "kotlinx-coroutines-swing" to 70, // awaitFrame is not tested
     "kotlinx-coroutines-javafx" to 39, // JavaFx is not tested on TC because its graphic subsystem cannot be initialized in headless mode
 
-    // TODO figure it out, these probably should be fixed
-    "kotlinx-coroutines-debug" to 84,
-    "kotlinx-coroutines-reactive" to 65,
+    // Re-evaluate this along with Kover update where deprecated with error+ functions are not considered as uncovered: IDEA-287459
     "kotlinx-coroutines-reactor" to 65,
-    "kotlinx-coroutines-rx2" to 78,
-    "kotlinx-coroutines-slf4j" to 81
+    "kotlinx-coroutines-rx2" to 78
 )
 
 extensions.configure<KoverExtension> {
@@ -51,4 +47,8 @@ subprojects {
             }
         }
     }
+
+    tasks.withType<KoverHtmlReportTask> {
+        htmlReportDir.set(file(rootProject.buildDir.toString() + "/kover/" + project.name + "/html"))
+    }
 }

integration/kotlinx-coroutines-slf4j/test/MDCContextTest.kt

@@ -102,9 +102,10 @@ class MDCContextTest : TestBase() {
         val mainDispatcher = kotlin.coroutines.coroutineContext[ContinuationInterceptor]!!
         withContext(Dispatchers.Default + MDCContext()) {
             assertEquals("myValue", MDC.get("myKey"))
+            assertEquals("myValue", coroutineContext[MDCContext]?.contextMap?.get("myKey"))
             withContext(mainDispatcher) {
                 assertEquals("myValue", MDC.get("myKey"))
             }
         }
     }
-}
+}

kotlinx-coroutines-debug/build.gradle

@@ -51,3 +51,15 @@ shadowJar {
     configurations = [project.configurations.shadowDeps]
     relocate('net.bytebuddy', 'kotlinx.coroutines.repackaged.net.bytebuddy')
 }
+
+def commonKoverExcludes =
+        // Never used, safety mechanism
+        ["kotlinx.coroutines.debug.internal.NoOpProbesKt"]
+
+tasks.koverHtmlReport {
+    excludes = commonKoverExcludes
+}
+
+tasks.koverVerify {
+    excludes = commonKoverExcludes
+}

kotlinx-coroutines-debug/test/ToStringTest.kt

@@ -8,6 +8,7 @@ import kotlinx.coroutines.*
 import kotlinx.coroutines.channels.*
 import org.junit.*
 import org.junit.Test
+import java.io.*
 import kotlin.coroutines.*
 import kotlin.test.*
 
@@ -105,6 +106,8 @@ class ToStringTest : TestBase() {
         expect(6)
         assertEquals(expected, DebugProbes.jobToString(root).trimEnd().trimStackTrace().trimPackage())
         assertEquals(expected, DebugProbes.scopeToString(CoroutineScope(root)).trimEnd().trimStackTrace().trimPackage())
+        assertEquals(expected, printToString { DebugProbes.printScope(CoroutineScope(root), it) }.trimEnd().trimStackTrace().trimPackage())
+        assertEquals(expected, printToString { DebugProbes.printJob(root, it) }.trimEnd().trimStackTrace().trimPackage())
 
         root.cancelAndJoin()
         finish(7)
@@ -145,4 +148,12 @@ class ToStringTest : TestBase() {
             }
         }
     }
+
+    private inline fun printToString(block: (PrintStream) -> Unit): String {
+        val baos = ByteArrayOutputStream()
+        val ps = PrintStream(baos)
+        block(ps)
+        ps.close()
+        return baos.toString()
+    }
 }

reactive/kotlinx-coroutines-reactive/build.gradle.kts

@@ -34,3 +34,17 @@ tasks.check {
 externalDocumentationLink(
     url = "https://www.reactive-streams.org/reactive-streams-$reactiveStreamsVersion-javadoc/"
 )
+
+val commonKoverExcludes = listOf(
+    "kotlinx.coroutines.reactive.FlowKt", // Deprecated
+    "kotlinx.coroutines.reactive.FlowKt__MigrationKt", // Deprecated
+    "kotlinx.coroutines.reactive.ConvertKt" // Deprecated
+)
+
+tasks.koverHtmlReport {
+    excludes = commonKoverExcludes
+}
+
+tasks.koverVerify {
+    excludes = commonKoverExcludes
+}

reactive/kotlinx-coroutines-reactor/build.gradle.kts

@@ -27,3 +27,15 @@ tasks {
 externalDocumentationLink(
     url = "https://projectreactor.io/docs/core/$reactorVersion/api/"
 )
+
+val commonKoverExcludes = listOf(
+    "kotlinx.coroutines.reactor.FlowKt" // Deprecated
+)
+
+tasks.koverHtmlReport {
+    excludes = commonKoverExcludes
+}
+
+tasks.koverVerify {
+    excludes = commonKoverExcludes
+}

ui/kotlinx-coroutines-android/src/HandlerDispatcher.kt

@@ -190,7 +190,7 @@ public suspend fun awaitFrame(): Long {
             postFrameCallback(choreographer, cont)
         }
     }
-    // post into looper thread thread to figure it out
+    // post into looper thread to figure it out
     return suspendCancellableCoroutine { cont ->
         Dispatchers.Main.dispatch(EmptyCoroutineContext, Runnable {
             updateChoreographerAndPostFrameCallback(cont)

ui/kotlinx-coroutines-android/test/AndroidExceptionPreHandlerTest.kt

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2016-2022 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package kotlinx.coroutines.android
+
+import kotlinx.coroutines.*
+import org.junit.Test
+import org.junit.runner.*
+import org.robolectric.*
+import org.robolectric.annotation.*
+import kotlin.test.*
+
+@RunWith(RobolectricTestRunner::class)
+@Config(manifest = Config.NONE, sdk = [27])
+class AndroidExceptionPreHandlerTest : TestBase() {
+    @Test
+    fun testUnhandledException() = runTest {
+        val previousHandler = Thread.getDefaultUncaughtExceptionHandler()
+        try {
+            Thread.setDefaultUncaughtExceptionHandler { _, e ->
+                expect(3)
+                assertIs<TestException>(e)
+            }
+            expect(1)
+            GlobalScope.launch(Dispatchers.Main) {
+                expect(2)
+                throw TestException()
+            }.join()
+            finish(4)
+        } finally {
+            Thread.setDefaultUncaughtExceptionHandler(previousHandler)
+        }
+    }
+}

ui/kotlinx-coroutines-android/test/HandlerDispatcherAsyncTest.kt

@@ -0,0 +1,145 @@
+/*
+ * Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package kotlinx.coroutines.android
+
+import android.os.*
+import kotlinx.coroutines.*
+import org.junit.Test
+import org.junit.runner.*
+import org.robolectric.*
+import org.robolectric.Shadows.*
+import org.robolectric.annotation.*
+import org.robolectric.shadows.*
+import org.robolectric.util.*
+import java.util.concurrent.*
+import kotlin.test.*
+
+@RunWith(RobolectricTestRunner::class)
+@Config(manifest = Config.NONE, sdk = [28])
+class HandlerDispatcherAsyncTest : TestBase() {
+
+    /**
+     * Because [Dispatchers.Main] is a singleton, we cannot vary its initialization behavior. As a
+     * result we only test its behavior on the newest API level and assert that it uses async
+     * messages. We rely on the other tests to exercise the variance of the mechanism that the main
+     * dispatcher uses to ensure it has correct behavior on all API levels.
+     */
+    @Test
+    fun mainIsAsync() = runTest {
+        ReflectionHelpers.setStaticField(Build.VERSION::class.java, "SDK_INT", 28)
+
+        val mainLooper = shadowOf(Looper.getMainLooper())
+        mainLooper.pause()
+        val mainMessageQueue = shadowOf(Looper.getMainLooper().queue)
+
+        val job = launch(Dispatchers.Main) {
+            expect(2)
+        }
+
+        val message = mainMessageQueue.head
+        assertTrue(message.isAsynchronous)
+        job.join(mainLooper)
+    }
+
+    @Test
+    fun asyncMessagesApi14() = runTest {
+        ReflectionHelpers.setStaticField(Build.VERSION::class.java, "SDK_INT", 14)
+
+        val main = Looper.getMainLooper().asHandler(async = true).asCoroutineDispatcher()
+
+        val mainLooper = shadowOf(Looper.getMainLooper())
+        mainLooper.pause()
+        val mainMessageQueue = shadowOf(Looper.getMainLooper().queue)
+
+        val job = launch(main) {
+            expect(2)
+        }
+
+        val message = mainMessageQueue.head
+        assertFalse(message.isAsynchronous)
+        job.join(mainLooper)
+    }
+
+    @Test
+    fun asyncMessagesApi16() = runTest {
+        ReflectionHelpers.setStaticField(Build.VERSION::class.java, "SDK_INT", 16)
+
+        val main = Looper.getMainLooper().asHandler(async = true).asCoroutineDispatcher()
+
+        val mainLooper = shadowOf(Looper.getMainLooper())
+        mainLooper.pause()
+        val mainMessageQueue = shadowOf(Looper.getMainLooper().queue)
+
+        val job = launch(main) {
+            expect(2)
+        }
+
+        val message = mainMessageQueue.head
+        assertTrue(message.isAsynchronous)
+        job.join(mainLooper)
+    }
+
+    @Test
+    fun asyncMessagesApi28() = runTest {
+        ReflectionHelpers.setStaticField(Build.VERSION::class.java, "SDK_INT", 28)
+
+        val main = Looper.getMainLooper().asHandler(async = true).asCoroutineDispatcher()
+
+        val mainLooper = shadowOf(Looper.getMainLooper())
+        mainLooper.pause()
+        val mainMessageQueue = shadowOf(Looper.getMainLooper().queue)
+
+        val job = launch(main) {
+            expect(2)
+        }
+
+        val message = mainMessageQueue.head
+        assertTrue(message.isAsynchronous)
+        job.join(mainLooper)
+    }
+
+    @Test
+    fun noAsyncMessagesIfNotRequested() = runTest {
+        ReflectionHelpers.setStaticField(Build.VERSION::class.java, "SDK_INT", 28)
+
+        val main = Looper.getMainLooper().asHandler(async = false).asCoroutineDispatcher()
+
+        val mainLooper = shadowOf(Looper.getMainLooper())
+        mainLooper.pause()
+        val mainMessageQueue = shadowOf(Looper.getMainLooper().queue)
+
+        val job = launch(main) {
+            expect(2)
+        }
+
+        val message = mainMessageQueue.head
+        assertFalse(message.isAsynchronous)
+        job.join(mainLooper)
+    }
+
+    @Test
+    fun testToString() {
+        ReflectionHelpers.setStaticField(Build.VERSION::class.java, "SDK_INT", 28)
+        val main = Looper.getMainLooper().asHandler(async = true).asCoroutineDispatcher("testName")
+        assertEquals("testName", main.toString())
+        assertEquals("testName.immediate", main.immediate.toString())
+        assertEquals("testName.immediate", main.immediate.immediate.toString())
+    }
+
+    private suspend fun Job.join(mainLooper: ShadowLooper) {
+        expect(1)
+        mainLooper.unPause()
+        join()
+        finish(3)
+    }
+
+    // TODO compile against API 23+ so this can be invoked without reflection.
+    private val Looper.queue: MessageQueue
+        get() = Looper::class.java.getDeclaredMethod("getQueue").invoke(this) as MessageQueue
+
+    // TODO compile against API 22+ so this can be invoked without reflection.
+    private val Message.isAsynchronous: Boolean
+        get() = Message::class.java.getDeclaredMethod("isAsynchronous").invoke(this) as Boolean
+}