def test_leader_empty_string(assert_pixels):
    assert_pixels('''
        RRRR____
        ________
    ''', '''
      <style>
        @page {
          size: 8px 2px;
        }
        body {
          color: red;
          font-family: weasyprint;
          font-size: 1px;
          line-height: 1;
        }
        div::after {
          color: blue;
          content: leader('');
        }
      </style>
      <div>aaaa</div>
    ''')
,
tests/draw/test_leader.py