Useless time consumption

1. Describe a situation in which you were able to use persuasion to successfully convince someone to see things your way.

That's all about using unit-tests on the frontend for documenting purpose. I really believe that they are wasting time activity.
Once I've been involved in "a very huge project" for two months. During staffing interview, I was asked about how am I documenting my code. I said that I write self-documenting code, which means easy to read and understand. But they had another idea. They thought that unit-tests is a documentation of the codebase by themselves. I never wrote tests for Vue.js, so I agreed. After a month of hard working on project with a team of 14 FE developers, I started searching for evidence that unit-tests are useful and really help to understand the code. And there was none. There were several questions from me regarding project architecture decisions also, so team lead initiated a retrospective meeting with Cola and snacks. When everyone confronted with evidence of significant time consumption on writing, maintaining and debugging tests, they had no objection, but unfortunately, the labour input was already approved by management and customer provided dedicated cost allocation. As an outcome, I'm pretty sure that unit-tests on frontend are a bad idea, but I want to believe, that sometimes I'll change my mind.