How would you test an external DB (Salesforce)

Hi, been at a company for almost a year now and cannot think of a decent way to start building some tests into the projects.

The issue I face is that almost everything goes to external services but mainly they use Salesforce as their 'database' and an Eloquent wrapper to make it feel local.

I have toyed with the idea of creating some custom work that will essentially call delete on whatever records are created on Salesforce at the end of a test but we have data and API request limits that will make TDD etc painful.

Anyone ever come across something similar?