RunBlockingTest.kt

package kotlinx.coroutines

import kotlinx.coroutines.testing.*
import kotlinx.coroutines.exceptions.*
import kotlin.coroutines.*
import kotlin.test.*
import kotlin.time.Duration.Companion.milliseconds
import kotlin.time.Duration.Companion.seconds

class RunBlockingTest : TestBase() {

    @Test
    fun testWithTimeoutBusyWait() = runTest {
        val value = withTimeoutOrNull(10) {
            while (isActive) {
                // Busy wait
            }
            "value"
        }

        assertEquals("value", value)
    }

    @Test
    fun testPrivateEventLoop() {
        expect(1)
        runBlocking {
            expect(2)
            assertIs<EventLoop>(coroutineContext[ContinuationInterceptor])
            yield() // is supported!
            expect(3)
        }
        finish(4)
    }

    @Test
    fun testOuterEventLoop() {
        expect(1)
        runBlocking {
            expect(2)
            val outerEventLoop = coroutineContext[ContinuationInterceptor] as EventLoop
            runBlocking(coroutineContext) {
                expect(3)
                // still same event loop
                assertSame(coroutineContext[ContinuationInterceptor], outerEventLoop)
                yield() // still works
                expect(4)
            }
            expect(5)
        }
        finish(6)
    }

    @Test
    fun testOtherDispatcher() = runTest {
        expect(1)
        val name = "RunBlockingTest.testOtherDispatcher"
        val thread = newSingleThreadContext(name)
        runBlocking(thread) {
            expect(2)
            assertSame(coroutineContext[ContinuationInterceptor], thread)
            assertTrue(currentThreadName().contains(name))
            yield() // should work
            expect(3)
        }
        finish(4)
        thread.close()
    }

    @Test
    fun testCancellation()  = runTest {
        newFixedThreadPoolContext(2, "testCancellation").use {
            val job = GlobalScope.launch(it) {
                runBlocking(coroutineContext) {
                    while (true) {
                        yield()
                    }
                }
            }

            runBlocking {
                job.cancelAndJoin()
            }
        }
    }

    @Test
    fun testCancelWithDelay() {
        // see https://github.com/Kotlin/kotlinx.coroutines/issues/586
        try {
            runBlocking {
                expect(1)
                coroutineContext.cancel()
                expect(2)
                try {
                    delay(1)
                    expectUnreached()
                } finally {
                    expect(3)
                }
            }
            expectUnreached()
        } catch (e: CancellationException) {
            finish(4)
        }
    }

    @Test
    fun testDispatchOnShutdown(): Unit = assertFailsWith<CancellationException> {
        runBlocking {
            expect(1)
            val job = launch(NonCancellable) {
                try {
                    expect(2)
                    delay(Long.MAX_VALUE)
                } finally {
                    finish(4)
                }
            }

            yield()
            expect(3)
            coroutineContext.cancel()
            job.cancel()
        }
    }.let { }

    @Test
    fun testDispatchOnShutdown2(): Unit = assertFailsWith<CancellationException> {
        runBlocking {
            coroutineContext.cancel()
            expect(1)
            val job = launch(NonCancellable, start = CoroutineStart.UNDISPATCHED) {
                try {
                    expect(2)
                    delay(Long.MAX_VALUE)
                } finally {
                    finish(4)
                }
            }

            expect(3)
            job.cancel()
        }
    }.let { }

    @Test
    fun testNestedRunBlocking() = runBlocking {
        delay(100)
        val value = runBlocking {
            delay(100)
            runBlocking {
                delay(100)
                1
            }
        }

        assertEquals(1, value)
    }

    @Test
    fun testIncompleteState() {
        val handle = runBlocking {
            // See #835
            coroutineContext[Job]!!.invokeOnCompletion { }
        }

        handle.dispose()
    }

    @Test
    fun testCancelledParent() {
        val job = Job()
        job.cancel()
        assertFailsWith<CancellationException> {
            runBlocking(job) {
                expectUnreached()
            }
        }
    }

    /** Tests that the delayed tasks scheduled on a closed `runBlocking` event loop get processed in reasonable time. */
    @Test
    fun testReschedulingDelayedTasks() {
        val job = runBlocking {
            val dispatcher = coroutineContext[ContinuationInterceptor]!!
            GlobalScope.launch(dispatcher) {
                delay(1.milliseconds)
            }
        }
        runBlocking {
            withTimeout(10.seconds) {
                job.join()
            }
        }
    }
}