Most common beginner Rails testing questions

What are the different kinds of Rails tests and when should I use each?
What are all the Rails testing tools and how do I use them?
What level of test coverage should I shoot for?
How do I make testing a habitual part of my development work?
Which test framework should I learn, RSpec or Minitest?
How do I add tests to an existing Rails project?
How do I set up a new Rails project for testing?
Should I be doing test-driven development?

Other beginner articles

A Rails testing “hello world” using RSpec and Capybara
A Rails model test “hello world”
My general approach to Rails testing
What kinds of Rails tests I write and what kinds I don’t
How to write a test when the test implementation isn’t obvious
Examples of pointless types of RSpec tests
Factories and fixtures in Rails
RSpec mocks and stubs in plain English
Why I recommend against using Cucumber
Rails scaffolding and TDD are incompatible (but that’s okay)
Where to start with introducing TDD to a new Rails app