import java.io.*;

File f = new File( basedir, "target/test-1-bin/unprefixed/maven-assembly-plugin.jar" );
File f2 = new File( basedir, "target/test-1-bin/prefixed/maven-assembly-plugin.jar" );

if ( !f.exists() || !f.isFile() )
{
    System.out.println( "File: " + f + " doesn't exist, or isn't a file." );
    return false;
}

if ( !f2.exists() || !f2.isFile() )
{
    System.out.println( "File: " + f2 + " doesn't exist, or isn't a file." );
    return false;
}

return true;