Just out of curiosity, have you simply tried searching all the text files that make up your Elixir codebase for SQL.Sandbox or even just Sandbox?
In my current application I don’t use the Ecto Sandbox either and everything in regards to testing and the database works the way I suspect you desire. However, if I or someone else had added code making use of the Ecto Sandbox to the project (a necessary step for it to be used: it’s fully opt in) and I wanted to get rid of it, but couldn’t: I’d do that simple brute force search to see what remnants might have been missed.
