@Test
public void blankNeedAppearance() {

    PDAcroForm mergeThis = new PDAcroForm(new PDDocument());
    mergeThis.setDefaultAppearance("this");
    PDAcroForm intoThis = new PDAcroForm(new PDDocument());
    intoThis.setDefaultAppearance("that");
    AcroFormUtils.mergeDefaults(mergeThis, intoThis);
    assertEquals("that", intoThis.getDefaultAppearance());
}