Houston, we have an Agile: Let's fire the testers and let the developers do the testing

If you look at the literature on Agile, there is no division into roles: a developer, a tester, an analyst - this is a team. You have the section on the project that closes the "questions" of testing, and the ratio of the group is one tester to 2 developers. But there came times of optimization and the balance of the team to become one tester for eight developers. In this ratio, the question arises: how to test and maintain quality in such a situation? 

 As part of my report, I will share my experience (fortunately, I got into such a situation) and choose a simple way - if there are no testers, we will make them from existing team members. I will talk about how I taught developers and analysts the craft of testing, what tools I used, how to learn the language of "developers," and why I did not like Cucumber.