A means to preserve logging on Android without breaking simple unit tests.

Logger.kt

import android.util.Log
import kotlin.reflect.KClass

/**
 * An interface meant to trivialize the mocking of Android's [Log] methods.
 */
interface Logger {

    fun v(message: String)
    fun d(message: String)
    fun i(message: String)
    fun w(message: String)
    fun e(message: String)
    fun wtf(message: String)
}

/**
 * Given a "tag" string, this function spits out an implementation of the [Logger] interface.
 * Powered by the Android [Log] class.
 */
fun getLogger(tag: String): Logger = object : Logger {

    override fun v(message: String) {
        Log.v(tag, message)
    }

    override fun d(message: String) {
        Log.d(tag, message)
    }

    override fun i(message: String) {
        Log.i(tag, message)
    }

    override fun w(message: String) {
        Log.w(tag, message)
    }

    override fun e(message: String) {
        Log.e(tag, message)
    }

    override fun wtf(message: String) {
        Log.wtf(tag, message)
    }
}

/**
 * Given a class reference, this function spits out an implementation of the [Logger] interface.
 * Powered by the Android [Log] class.
 */
fun getLogger(classRef: KClass<out Any>): Logger {
    return getLogger(classRef.simpleName ?: "AnonymousObject")
}