Unit tests are great, but on their own, they don't tell you whether your application behaves as expected. Can a user access someone else's records? Do your translations work correctly based on request headers? Learn how to write relevant Behat tests, how to set everything up and how a backend and a frontend can be developed in parallel.
I am a web developer, team lead, project rescue expert, Pluralsight author, public speaker and former conference organizer. I enjoy realizing seemingly impossible things. I have been coding since 1997.