<?php
        global $post;
        $categories = get_the_category();
        foreach ($categories as $category) :?>
            <ul>
            <?php
                $posts = get_posts('numberposts=3&category='. $category->term_id);
                foreach($posts as $post) : ?>
                <li>
                    <a href="<?php the_permalink(); ?>">
<?php the_title(); ?>
    </a>            </li>
            <?php endforeach; ?>
    <?php endforeach; ?>
            </ul>

<?php
$currentPostID = $post->ID;

global $post;
$categories = get_the_category();
foreach ($categories as $category) :?>
  <ul>
      <?php
      $posts = get_posts('numberposts=3&category='. $category->term_id);
          foreach($posts as $post) : ?>
           <?php  if ($currentPostID != $post->ID) {
                $test_value = get_post_meta( $post->ID, 'test', true );
                ?>
                 <li>
                    <a href="<?php the_permalink(); ?>">
                       <?php if ( ! empty( $test_value ) ) {echo $test_value; } else { echo 'Nothing'; } ?>
                    </a>
                 </li><?php
              }?>
          <?php endforeach; ?>
  </ul>
<?php endforeach; ?>