@file:JvmName("TestDispatchers")

package kotlinx.coroutines.test

import kotlinx.coroutines.*

import kotlinx.coroutines.test.internal.*

import kotlin.jvm.*

/**

* Sets the given [dispatcher] as an underlying dispatcher of [Dispatchers.Main].

* All subsequent usages of [Dispatchers.Main] will use the given [dispatcher] under the hood.

*

* Using [TestDispatcher] as an argument has special behavior: subsequently-called [runTest], as well as

* [TestScope] and test dispatcher constructors, will use the [TestCoroutineScheduler] of the provided dispatcher.

*

* It is unsafe to call this method if alive coroutines launched in [Dispatchers.Main] exist.

*/

@ExperimentalCoroutinesApi

public fun Dispatchers.setMain(dispatcher: CoroutineDispatcher) {

require(dispatcher !is TestMainDispatcher) { "Dispatchers.setMain(Dispatchers.Main) is prohibited, probably Dispatchers.resetMain() should be used instead" }

getTestMainDispatcher().setDispatcher(dispatcher)

}

/**

* Resets state of the [Dispatchers.Main] to the original main dispatcher.

*

* For example, in Android, the Main thread dispatcher will be set as [Dispatchers.Main].

* This method undoes a dependency injection performed for tests, and so should be used in tear down (`@After`) methods.

*

* It is unsafe to call this method if alive coroutines launched in [Dispatchers.Main] exist.

*/

@ExperimentalCoroutinesApi

public fun Dispatchers.resetMain() {

getTestMainDispatcher().resetDispatcher()

}