Outside-in Testing

Outside-in testing process

The process we’ll use to manage the feature tests is sometimes called outside-in testing. We use Capybara to write a test from the outside and use that test to drive the unit tests. In the same way TDD uses a failing unit test to drive code, outside-in testing uses a failing acceptance test (or a failing line in an acceptance test) to drive the creation of unit tests.

The process is illustrated in the following figure: we’re assuming creating a new user-facing feature in a Rails application.