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

<!DOCTYPE module PUBLIC "-//Google Inc.//DTD Google Web Toolkit 2.0//EN"
        "http://google-web-toolkit.googlecode.com/svn/releases/2.0/distro-source/core/src/gwt-module.dtd">
<module>
  <inherits name="com.google.gwt.resources.Resources" />

  <!-- Enable auto-conversion -->
  <set-configuration-property name="CssResource.conversionMode" value="lenient" />
  <extend-configuration-property name="CssResource.allowedAtRules" value="dontIgnoreThis" />
  <extend-configuration-property name="CssResource.allowedAtRules" value="dontIgnoreThisToo" />
</module>