Sleep sort

FlowTest.kt

package com.example.android.flow

import com.google.common.truth.Truth.assertThat
import kotlinx.coroutines.async
import kotlinx.coroutines.awaitAll
import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.channelFlow
import kotlinx.coroutines.flow.toList
import kotlinx.coroutines.runBlocking
import org.junit.Test

class FlowTest {

    fun sleepSort(input: List<Int>): Flow<Int> {
        return channelFlow {
            input.map { i ->
                async {
                    delay(i * 100L)
                    send(i)
                }
            }.awaitAll()
        }
    }

    @Test
    fun sorted() = runBlocking {
        val input = listOf(9, 0, 8, 1, 7, 2, 6, 3, 5, 4)
        assertThat(sleepSort(input).toList()).isOrdered()
    }
}