user/test/com/google/gwt/resources/GssResourceRTLTest.gwt.xml

<module>
  <inherits name="com.google.gwt.resources.Resources" />
  <inherits name="com.google.gwt.i18n.I18N"/>

  <!-- Use an RTL language -->
  <extend-property name="locale" values="ar"/>
  <set-property name="locale" value="ar" />
  <!-- enable GSS -->
  <set-configuration-property name="CssResource.enableGss" value="true" />
  <set-configuration-property name="CssResource.conversionMode" value="strict" />
</module>