def test_grouping():
 t = QTable(MIXIN_COLS)
 t['index'] = ['a', 'b', 'b', 'c']
 with pytest.raises(NotImplementedError):
  t.group_by('index')

def test_grouping ( ) : t = QTable ( MIXIN_COLS ) t [ 'index' ] = [ 'a' , 'b' , 'b' , 'c' ] with pytest . raises ( NotImplementedError ) : t . group_by ( 'index' )
test grouping with mixin columns .