Left/Right float button inside div

Change display:inline to display:inline-block

.test {
  width:200px;
  display:inline-block;
  overflow: auto;
  white-space: nowrap;
  margin:0px auto;
  border:1px red solid;
}

You can use justify-content: space-between in .test like so:

.test {
  display: flex;
  justify-content: space-between;
  width: 20rem;
  border: .1rem red solid;
}
<div class="test">
  <button>test</button>
  <button>test</button>
</div>

For those who want to use Bootstrap 4 can use justify-content-between:

div {
  width: 20rem;
  border: .1rem red solid;
}
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" rel="stylesheet" />
<div class="d-flex justify-content-between">
  <button>test</button>
  <button>test</button>
</div>

Tags:

Html

Css