为什么span标签会下降到子行

Question

https://jsfiddle.net/p3qwz4xu/

我该如何解决。我希望整个电话号码都在同一行。

输出

Call 1234 456
789

所需的输出

Call 1234 456 789

HTML不会更改。

.call {
  margin-left: 3%;
  font-size: 1.5em;
}

.phone {
  font-size: 2em;
}

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

<div class="container">
  <div class="row">
    <div class="test">
      <span class="call">Call</span>
      <span class="phone">1234 456 789</span>
    </div>
  </div>
</div>