In the company I work we have to update the current aplication to Dot Net Core 2.1 and Angular 7, but the current aplication has a lot of Stored Procedures and DataSources, the company and veteran developers don't want to get rid of their Stored Procedures, so what pattern can I use for a Data Access Layer or something like that, to deal with them, I was thinking on something like Repositories or use CQRS to call the Stored Procedures but, how can I test that?

Thank you for your suggestions