'Test tables with some common columns, but different number of columns
overall.'

def test_different_table_field_counts(self):

    ca = Column('A', format='L', array=[True, False])
    cb = Column('B', format='L', array=[True, False])
    cc = Column('C', format='L', array=[True, False])
    ta = BinTableHDU.from_columns([cb])
    tb = BinTableHDU.from_columns([ca, cb, cc])
    diff = TableDataDiff(ta.data, tb.data)
    assert (not diff.identical)
    assert (diff.diff_column_count == (1, 3))
    assert (len(diff.common_columns) == 1)
    assert (diff.common_column_names == set(['b']))
    assert (diff.diff_column_names == ([], ['A', 'C']))
    assert (diff.diff_ratio == 0)
    assert (diff.diff_total == 0)
    report = diff.report()
    assert ('    Tables    have    different    number    of    columns:' in report)
    assert ('        a:    1\n        b:    3' in report)
