Use assert taglib in plugin test

git-svn-id: https://svn.apache.org/repos/asf/maven/maven-1/plugins/trunk@115596 13f79535-47bb-0310-9956-ffa450edef68

clean/src/plugin-test/maven.xml

@@ -15,7 +15,9 @@
  * limitations under the License.
  */
  -->
-<project xmlns:j="jelly:core" xmlns:u="jelly:util">
+<project xmlns:assert="assert"
+         xmlns:j="jelly:core" 
+         xmlns:u="jelly:util">
 
   <goal name="testPlugin" prereqs="test-clean">
   </goal>
@@ -24,10 +26,6 @@
     <mkdir dir="${maven.build.dir}"/>
     <attainGoal name="clean"/>
 
-    <u:file var="target" name="${maven.build.dir}"/>
-    <j:if test="${(target.exists())}">
-      <fail>maven.build.dir was not deleted</fail>
-    </j:if>
-
+    <assert:assertFileNotFound file="${maven.build.dir}"/>
   </goal>
 </project>