common/kotlinx-coroutines-core-common/test/selects/SelectDeferredTest.kt

/*
 * Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
 */

@file:Suppress("NAMED_ARGUMENTS_NOT_ALLOWED") // KT-21913

package kotlinx.coroutines.experimental.selects

import kotlinx.coroutines.experimental.*
import kotlin.coroutines.experimental.*
import kotlin.test.*

class SelectDeferredTest : TestBase() {
    @Test
    fun testSimpleReturnsImmediately() = runTest {
        expect(1)
        val d1 = async(coroutineContext) {
            expect(3)
            42
        }
        expect(2)
        val res = select<String> {
            d1.onAwait { v ->
                expect(4)
                assertEquals(42, v)
                "OK"
            }
        }
        expect(5)
        assertEquals("OK", res)
        finish(6)
    }

    @Test
    fun testSimpleWithYield() = runTest {
        expect(1)
        val d1 = async(coroutineContext) {
            expect(3)
            42
        }
        launch(coroutineContext) {
            expect(4)
            yield() // back to main
            expect(6)
        }
        expect(2)
        val res = select<String> {
            d1.onAwait { v ->
                expect(5)
                assertEquals(42, v)
                yield() // to launch
                expect(7)
                "OK"
            }
        }
        finish(8)
        assertEquals("OK", res)
    }

    @Test
    fun testSelectIncompleteLazy() = runTest {
        expect(1)
        val d1 = async(coroutineContext, CoroutineStart.LAZY) {
            expect(5)
            42
        }
        launch(coroutineContext) {
            expect(3)
            val res = select<String> {
                d1.onAwait { v ->
                    expect(7)
                    assertEquals(42, v)
                    "OK"
                }
            }
            expect(8)
            assertEquals("OK", res)
        }
        expect(2)
        yield() // to launch
        expect(4)
        yield() // to started async
        expect(6)
        yield() // to triggered select
        finish(9)
    }

    @Test
    fun testSelectTwo() = runTest {
        expect(1)
        val d1 = async(coroutineContext) {
            expect(3)
            yield() // to the other deffered
            expect(5)
            yield() // to fired select
            expect(7)
            "d1"
        }
        val d2 = async(coroutineContext) {
            expect(4)
            "d2" // returns result
        }
        expect(2)
        val res = select<String> {
            d1.onAwait {
                expectUnreached()
                "FAIL"
            }
            d2.onAwait { v2 ->
                expect(6)
                assertEquals("d2", v2)
                yield() // to first deferred
                expect(8)
                "OK"
            }
        }
        assertEquals("OK", res)
        finish(9)
    }

    @Test
    fun testSelectCancel() = runTest(
        expected = { it is JobCancellationException }
    ) {
        expect(1)
        val d = CompletableDeferred<String>()
        launch (coroutineContext) {
            finish(3)
            d.cancel() // will cancel after select starts
        }
        expect(2)
        select<Unit> {
            d.onAwait {
                expectUnreached() // will not select
            }
        }
        expectUnreached()
    }

}