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/*
* Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
*/
package kotlinx.coroutines.sync
import kotlinx.coroutines.*
import kotlin.test.*
class MutexTest : TestBase() {
@Test
fun testSimple() = runTest {
val mutex = Mutex()
expect(1)
launch {
expect(4)
mutex.lock() // suspends
expect(7) // now got lock
mutex.unlock()
expect(8)
}
expect(2)
mutex.lock() // locked
expect(3)
yield() // yield to child
expect(5)
mutex.unlock()
expect(6)
yield() // now child has lock
finish(9)
}
@Test
fun tryLockTest() {
val mutex = Mutex()
assertFalse(mutex.isLocked)
assertTrue(mutex.tryLock())
assertTrue(mutex.isLocked)
assertFalse(mutex.tryLock())
assertTrue(mutex.isLocked)
mutex.unlock()
assertFalse(mutex.isLocked)
assertTrue(mutex.tryLock())
assertTrue(mutex.isLocked)
assertFalse(mutex.tryLock())
assertTrue(mutex.isLocked)
mutex.unlock()
assertFalse(mutex.isLocked)
}
@Test
fun withLockTest() = runTest {
val mutex = Mutex()
assertFalse(mutex.isLocked)
mutex.withLock {
assertTrue(mutex.isLocked)
}
assertFalse(mutex.isLocked)
}
@Test
fun testUnconfinedStackOverflow() {
val waiters = 10000
val mutex = Mutex(true)
var done = 0
repeat(waiters) {
GlobalScope.launch(Dispatchers.Unconfined) { // a lot of unconfined waiters
mutex.withLock {
done++
}
}
}
mutex.unlock() // should not produce StackOverflowError
assertEquals(waiters, done)
}
@Test
fun holdLock() = runTest {
val mutex = Mutex()
val firstOwner = Any()
val secondOwner = Any()
// no lock
assertFalse(mutex.holdsLock(firstOwner))
assertFalse(mutex.holdsLock(secondOwner))
// owner firstOwner
mutex.lock(firstOwner)
val secondLockJob = launch {
mutex.lock(secondOwner)
}
assertTrue(mutex.holdsLock(firstOwner))
assertFalse(mutex.holdsLock(secondOwner))
// owner secondOwner
mutex.unlock(firstOwner)
secondLockJob.join()
assertFalse(mutex.holdsLock(firstOwner))
assertTrue(mutex.holdsLock(secondOwner))
mutex.unlock(secondOwner)
// no lock
assertFalse(mutex.holdsLock(firstOwner))
assertFalse(mutex.holdsLock(secondOwner))
}
}
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