commonTest.flow.terminal.CountTest.kt Maven / Gradle / Ivy

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Coroutines support libraries for Kotlin

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/*
 * Copyright 2016-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
 */

package kotlinx.coroutines.flow

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

class CountTest : TestBase() {
    @Test
    fun testCount() = runTest {
        val flow = flowOf(239, 240)
        assertEquals(2, flow.count())
        assertEquals(2, flow.count { true })
        assertEquals(1, flow.count { it % 2 == 0})
        assertEquals(0, flow.count { false })
    }

    @Test
    fun testNoValues() = runTest {
        assertEquals(0, flowOf().count())
        assertEquals(0, flowOf().count { false })
        assertEquals(0, flowOf().count { true })
    }

    @Test
    fun testException() = runTest {
        val flow = flow {
            throw TestException()
        }

        assertFailsWith { flow.count() }
        assertFailsWith { flow.count { false } }
    }

    @Test
    fun testExceptionAfterValue() = runTest {
        val flow = flow {
            emit(1)
            throw TestException()
        }

        assertFailsWith { flow.count() }
        assertFailsWith { flow.count { false } }
    }
}