src/it/clean-custom-files/verify.bsh

import java.io.*;
import java.util.*;
import java.util.regex.*;

import org.codehaus.plexus.util.*;

File buildFile = new File( basedir, "build.xml" );
System.out.println( "Checking for absence of " + buildFile );
if ( buildFile.exists() )
{
    throw new IllegalStateException( "Custom build.xml was not deleted!" );
}

return true;