How to solve Error:(23, 17)"Failed to resolve: junit:junit:4.12" in Android Studio

Make sure that you are connected to internet.

Expand the Gradle Scripts

Double click on build.gradle (Module: app)

And paste following code below line apply plugin: 'com.android.application'

repositories {

    maven { url 'http://repo1.maven.org/maven2' }

    jcenter { url "http://jcenter.bintray.com/" }

}

Run your project and now it should work.