Understanding Test-Driven Development with RSpec in Ruby on Rails
If you’re a developer, then you have already performed a software test, whether you realize it or not. When you write a piece of software, to see if it's working, that's testing.
When you create a webform, then submit the form to see if it successfully adds the data to the database; that’s testing. When you submit the same form again, with the wrong input, to see if it rejects the form and tells the user there’s a problem, that’s also testing but manual testing.