def test_custom_derived_cols_from_df(test_data):
 ds = ChartDataSource.from_data(test_data.pd_data, dims=('x', 'y'), column_assigner=NumericalColumnsAssigner)
 assert (ds['y'] == ['col1', 'col2'])

def test_custom_derived_cols_from_df ( test_data ) : ds = ChartDataSource . from_data ( test_data . pd_data , dims = ( 'x' , 'y' ) , column_assigner = NumericalColumnsAssigner ) assert ( ds [ 'y' ] == [ 'col1' , 'col2' ] )
wide dataframe columns assigned to y dimension for the chart .