kotlin-coroutines - 如何对MutableSharedFlow (replay = 0)发出值进行单元测试？

Question

我无法弄清楚如何测试带有SharedFlow的replay=0发出的值。

import kotlinx.coroutines.flow.MutableSharedFlow
import kotlinx.coroutines.runBlocking
import org.junit.Test

class ShowcaseTest {

    @Test
    fun testIntSharedFlowFlow() {
        val intSharedFlow = MutableSharedFlow<Int>()

        runBlocking {
            intSharedFlow.emit(1)
        }
        
        // Does not work as there is no buffer because MutableSharedFlow(replay=0)
        assert(intSharedFlow.replayCache.first() == 1)
    }
}

Answer 1

您可以改用tryEmit()并验证返回的结果
更新:
考虑使用Turbine
例如:

sharedFlow.test {
    sharedFlow.emit(1)
    assertEquals(expected = 1, expectItem())
    cancelAndIgnoreRemainingEvents()

}