CustomRobolectricRunner.txt

//After creating your class extend, RobolectricTestRunner
//Create a cunstructor
//then inside your constructer, put this code inside it

 super(testClass);
 String buildVariant = (BuildConfig.FLAVOR.isEmpty()
 ? "" : BuildConfig.FLAVOR+ "/") + BuildConfig.BUILD_TYPE;
 String intermediatesPath = BuildConfig.class.getResource("")
 .toString().replace("file:", "");
 intermediatesPath = intermediatesPath
 .substring(0, intermediatesPath.indexOf("/classes"));

 System.setProperty("android.package",
 BuildConfig.APPLICATION_ID);
 System.setProperty("android.manifest",
 intermediatesPath + "/manifests/full/"
 + buildVariant + "/AndroidManifest.xml");
 System.setProperty("android.resources",
 intermediatesPath + "/res/" + buildVariant);
 System.setProperty("android.assets",
 intermediatesPath + "/assets/" + buildVariant);
 
}