@Test
public void testHeaderSizeNullHeaderValue() {

    final String[] alternate = { 
            null, 
            null, 
            };
    JXTable xTable = new JXTable(10, 2);
    xTable.getColumn(0).setHeaderValue(alternate[0]);
    xTable.getColumn(1).setHeaderValue(alternate[1]);
    assertTrue("header height must be > 0", xTable.getTableHeader().getPreferredSize().height > 0);
}