@Test
  public void testErase() {
    engine.erase();
    Assert.assertTrue("Erase() - Buffer isn't empty", buffer.getText().equals(""));
    Assert.assertTrue(
        "Erase() - Selection isn't (0, 0)",
        selection.getStart() == 0 && selection.getLength() == 0);

    buffer.setText("test");
    engine.erase();
    Assert.assertTrue(
        "Erase() - Buffer content isn't the set text", buffer.getText().equals("test"));
    Assert.assertTrue(
        "Erase() - Selection isn't (0, 0)",
        selection.getStart() == 0 && selection.getLength() == 0);

    selection.setStart(4);
    engine.erase();
    Assert.assertTrue(
        "Erase() - Buffer content isn't the set text", buffer.getText().equals("tes"));
    Assert.assertTrue(
        "Erase() - Selection isn't (3, 0)",
        selection.getStart() == 3 && selection.getLength() == 0);

    selection.setStart(0);
    selection.setLength(3);
    engine.erase();
    Assert.assertTrue("Erase() - Buffer content isn't the set text", buffer.getText().equals(""));
    Assert.assertTrue(
        "Erase() - Selection isn't (0, 0)",
        selection.getStart() == 0 && selection.getLength() == 0);
  }