Fix hanging RunInterruptibleStressTest on Windows with JDK 1.6 (Kotlin#2145)

The test is improved so that it fails, not hangs, on a failure. However, it will not pass on Windows + JDK 1.6 due to a bug in JDK (which can be easily confirmed with this modification to a test), so it excluded when running on JDK 1.6.

Fixes Kotlin#2144

Author: elizarov

kotlinx-coroutines-core/build.gradle

@@ -131,6 +131,7 @@ task jdk16Test(type: Test, dependsOn: [compileTestKotlinJvm, checkJdk16]) {
     exclude '**/*LCStressTest.*' // lin-check tests use LinChecker which needs JDK8
     exclude '**/exceptions/**'   // exceptions tests check suppressed exception which needs JDK8
     exclude '**/ExceptionsGuideTest.*'
+    exclude '**/RunInterruptibleStressTest.*' // fails on JDK 1.6 due to JDK bug
 }
 
 // Run these tests only during nightly stress test

kotlinx-coroutines-core/jvm/test/RunInterruptibleStressTest.kt

@@ -9,25 +9,29 @@ import org.junit.Test
 import java.util.concurrent.atomic.*
 import kotlin.test.*
 
+/**
+ * Stress test for [runInterruptible].
+ * It does not pass on JDK 1.6 on Windows: [Thread.sleep] times out without being interrupted despite the
+ * fact that thread interruption flag is set.
+ */
 class RunInterruptibleStressTest : TestBase() {
-
     @get:Rule
     val dispatcher = ExecutorRule(4)
-    private val REPEAT_TIMES = 1000 * stressTestMultiplier
+    private val repeatTimes = 1000 * stressTestMultiplier
 
     @Test
-    fun testStress() = runBlocking {
-        val interruptLeak = AtomicBoolean(false)
+    fun testStress() = runTest {
         val enterCount = AtomicInteger(0)
         val interruptedCount = AtomicInteger(0)
 
-        repeat(REPEAT_TIMES) {
+        repeat(repeatTimes) {
             val job = launch(dispatcher) {
                 try {
                     runInterruptible {
                         enterCount.incrementAndGet()
                         try {
-                            Thread.sleep(Long.MAX_VALUE)
+                            Thread.sleep(10_000)
+                            error("Sleep was not interrupted, Thread.isInterrupted=${Thread.currentThread().isInterrupted}")
                         } catch (e: InterruptedException) {
                             interruptedCount.incrementAndGet()
                             throw e
@@ -36,19 +40,17 @@ class RunInterruptibleStressTest : TestBase() {
                 } catch (e: CancellationException) {
                     // Expected
                 } finally {
-                    interruptLeak.set(interruptLeak.get() || Thread.currentThread().isInterrupted)
+                    assertFalse(Thread.currentThread().isInterrupted, "Interrupt flag should not leak")
                 }
             }
             // Add dispatch delay
             val cancelJob = launch(dispatcher) {
                 job.cancel()
             }
-
-            job.start()
             joinAll(job, cancelJob)
         }
-
-        assertFalse(interruptLeak.get())
+        println("Entered runInterruptible ${enterCount.get()} times")
+        assertTrue(enterCount.get() > 0) // ensure timing is Ok and we don't cancel it all prematurely
         assertEquals(enterCount.get(), interruptedCount.get())
     }
 }