Created
October 16, 2020 21:50
-
-
Save GregKluska/773b49320ab3225ad4b661c26a53f2d0 to your computer and use it in GitHub Desktop.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| /* | |
| * Copyright (C) 2019 The Android Open Source Project | |
| * | |
| * Licensed under the Apache License, Version 2.0 (the "License"); | |
| * you may not use this file except in compliance with the License. | |
| * You may obtain a copy of the License at | |
| * | |
| * http://www.apache.org/licenses/LICENSE-2.0 | |
| * | |
| * Unless required by applicable law or agreed to in writing, software | |
| * distributed under the License is distributed on an "AS IS" BASIS, | |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| * See the License for the specific language governing permissions and | |
| * limitations under the License. | |
| */ | |
| import androidx.annotation.VisibleForTesting | |
| import androidx.lifecycle.LiveData | |
| import androidx.lifecycle.Observer | |
| import java.util.concurrent.CountDownLatch | |
| import java.util.concurrent.TimeUnit | |
| import java.util.concurrent.TimeoutException | |
| /** | |
| * Gets the value of a [LiveData] or waits for it to have one, with a timeout. | |
| * | |
| * Use this extension from host-side (JVM) tests. It's recommended to use it alongside | |
| * `InstantTaskExecutorRule` or a similar mechanism to execute tasks synchronously. | |
| */ | |
| @VisibleForTesting(otherwise = VisibleForTesting.NONE) | |
| fun <T> LiveData<T>.getOrAwaitValue( | |
| time: Long = 2, | |
| timeUnit: TimeUnit = TimeUnit.SECONDS, | |
| afterObserve: () -> Unit = {} | |
| ): T { | |
| var data: T? = null | |
| val latch = CountDownLatch(1) | |
| val observer = object : Observer<T> { | |
| override fun onChanged(o: T?) { | |
| data = o | |
| latch.countDown() | |
| [email protected](this) | |
| } | |
| } | |
| this.observeForever(observer) | |
| try { | |
| afterObserve.invoke() | |
| // Don't wait indefinitely if the LiveData is not set. | |
| if (!latch.await(time, timeUnit)) { | |
| throw TimeoutException("LiveData value was never set.") | |
| } | |
| } finally { | |
| this.removeObserver(observer) | |
| } | |
| @Suppress("UNCHECKED_CAST") | |
| return data as T | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment