user/test/com/google/gwt/uibinder/test/UiBinderWithGss.gwt.xml

<module>
  <inherits name="com.google.gwt.user.User" />
  <inherits name="com.google.gwt.debug.Debug"/>
  <inherits name="com.google.gwt.junit.JUnit"/>

  <set-configuration-property name="CssResource.enableGss" value="true" />
  <set-configuration-property name="CssResource.conversionMode" value="strict" />
</module>