Fix unittest.

Author: prwater

build.xml

@@ -30,7 +30,7 @@
 
     <!-- Runs all unit tests -->
     <target name="unit">
-        <exec command="bin/phpunit" passthru="true" checkreturn="true"/>
+        <exec executable="bin/phpunit" passthru="true" checkreturn="true"/>
     </target>
 
     <target name="build">