public class LocaleRule implements TestRule {

   private final Locale[] mLocales;
   private Locale mDeviceLocale;

   public LocaleRule(Locale... locales) {
       mLocales = locales;
   }

   @Override
   public Statement apply(final Statement base, Description description) {
       return new Statement() {
           @Override
           public void evaluate() throws Throwable {
               try {
                   if (mLocales != null) {
                       mDeviceLocale = Locale.getDefault();

                       for (Locale locale : mLocales) {
                           setLocale(locale);
                           base.evaluate();
                       }
                   }
               } finally {
                   if (mDeviceLocale != null) {
                       setLocale(mDeviceLocale);
                   }
               }
           }
       };
   }

   private void setLocale(Locale locale) {
       Resources resources = InstrumentationRegistry
            .getTargetContext()
            .getResources();

       Locale.setDefault(locale);
       Configuration config = resources.getConfiguration();
       config.setLocale(locale);
       DisplayMetrics displayMetrics = resources.getDisplayMetrics();
       resources.updateConfiguration(config, displayMetrics);
   }
}