[Multiple Datasource Test] Add test for data_source_item

[yujin-emma]

Is your feature request related to a problem? Please describe.

Add test for data_source_item Describe the solution you'd like

Add test for data_source_item Describe alternatives you've considered

A clear and concise description of any alternative solutions or features you've considered.

Additional context

Add any other context or screenshots about the feature request here.