title: Gradle's dependency cache may be corrupt
body: <p>I already tried to Invalidate/Cache and restart</p>
  
  <p>also tried to remove .gradle and gradle file..
  but this problem still shows up.</p>
  
  <blockquote>
    <p>Error:Unable to find method
    'com.android.build.gradle.BaseExtension.getTestVariants()Lorg/gradle/api/internal/DefaultDomainObjectSet;'.
    Possible causes for this unexpected error include:<ul><li>Gradle's
    dependency cache may be corrupt (this sometimes occurs after a network
    connection timeout.) Re-download dependencies
    and sync project (requires network)</li><li>The state of a Gradle
    build process (daemon) may be corrupt. Stopping all Gradle daemons may
    solve this problem. Stop Gradle build
    processes (requires restart)</li><li>Your project may be using a
    third-party plugin which is not compatible with the other plugins in
    the project or the version of Gradle requested by the
    project.</li></ul>In the case of corrupt Gradle processes, you can
    also try closing the IDE and then killing all Java processes.</p>
  </blockquote>
  
  <p>Any thoughts?</p>
  
  <p>Your help will be appreciated Thanks!</p>