Kotlin extension to allow Unit tests on Android LiveData

LiveData.ext.kt

package com.tinmegali.daggerwithkotlin.room

import android.arch.lifecycle.LiveData
import android.arch.lifecycle.Observer
import java.util.concurrent.CountDownLatch
import java.util.concurrent.TimeUnit

// Extension to allow unit tests on LiveData
// discussion on: https://stackoverflow.com/questions/44270688/unit-testing-room-and-livedata

fun <T> LiveData<T>.blockingObserve(): T? {
    var value: T? = null
    val latch = CountDownLatch(1)
    val innerObserver = Observer<T> {
        value = it
        latch.countDown()
    }
    observeForever(innerObserver)
    latch.await(2, TimeUnit.SECONDS)
    return value
}