RSpec/Capybara integration tests: the ultimate guide

When I started learning about Rails testing and RSpec I discovered that there are many different kinds of tests. I encountered terms like “model spec”, “controller spec”, “view spec”, “request spec”, “route spec”, “feature spec”, and more. I asked myself: Why do these different types of tests exist? Do I need to use all of them? Are some more important than others?As I’ve gained experience with Rails testing I’ve come to believe that yes, some types of tests (or, to use the RSpec terminology, “specs”) are more important than other types of specs and no, I don’t need to use all of types of specs that RSpec offers. Some types of specs I never use at all (e.g. view specs).