Card-Columns Bootstrap v4

Want to remove the space in between the cards

HTML

<script src="//code.jquery.com/jquery-3.3.1.slim.min.js"></script>
<link rel="stylesheet" href="//stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css">
<script src="//cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js"></script>
<script src="//stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">

<main role="main" class="container-fluid free">
      <div class="card-columns">
        <div class="card" style="width:60%;">
          <div class="card-body">
            <h5 class="card-title">Test1</h5>
            <p class="card-text">test</p>
          </div>
        </div>
        <div class="card">
          <div class="card-body">
            <h5 class="card-title">Test2</h5>
          </div>
        </div>
      </div>
    </main>

CSS

.row {
  background: #f8f9fa;
  margin-top: 20px;
}

.col {
  border: solid 1px #6c757d;
  padding: 10px;
}