I got to listen to a discussion today where a topic was if a team kanban board should have a "ready for testing" column.
I am happy that the discussion ended with the decision not to have it.
I am happy on that because in the world of software development, testing is not a phase to happen somewhere after programming and before pushing something to production.
If/as testing is about raising good questions, seeking answers to those questions, and about exploring risks and opportunities - it should happen all the time. From the beginning when thinking if the thing should be built at all, into the end when analysing and observing the actual impacts.
Everything that happens between is about doing, and any extra column, phase and handover you create inside this is going to hurt you.