1 /*
2  * Copyright (C) 2024 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package com.google.jetpackcamera.feature.preview.rules
17 
18 import kotlinx.coroutines.CoroutineDispatcher
19 import kotlinx.coroutines.Dispatchers
20 import kotlinx.coroutines.ExperimentalCoroutinesApi
21 import kotlinx.coroutines.test.resetMain
22 import kotlinx.coroutines.test.setMain
23 import org.junit.rules.TestRule
24 import org.junit.runner.Description
25 import org.junit.runners.model.Statement
26 
27 class MainDispatcherRule(private val dispatcher: CoroutineDispatcher) : TestRule {
28     @OptIn(ExperimentalCoroutinesApi::class)
applynull29     override fun apply(base: Statement?, description: Description?) = object : Statement() {
30         override fun evaluate() {
31             Dispatchers.setMain(dispatcher)
32             try {
33                 base!!.evaluate()
34             } finally {
35                 Dispatchers.resetMain()
36             }
37         }
38     }
39 }
40