How to encourage team/senior developers to write mandatory unit testings?
Team background and my role
I am an iOS developer, working in a team of 6-7 members. There are only two iOS developers, including me. The senior developer is also the lead for iOS applications. I report to my senior developer and he reports to the manager. I am also excluded from most of the meetings with the manager, backend team, and QA. To make things even more clear, only this senior guy give me tasks and instructions on what to do. [I do share my thoughts with the entire team even though I m excluded most of the time. Some got attention.]
This senior iOS developer agrees on the importance of writing unit tests and can even talk about unit testings for the whole day. But in reality, I am the only one writing test cases. He does not even bother updating test cases when he changes classes written by me. Although he does not stop me from writing unit tests for his code, he does try to change direction.
In this situation, as a junior developer, how do I encourage my senior developer to commit to writing unit tests? Note: The manager is from a non-technical background.