Test your Drupal site's functionality in a human-readable format. Behavior-driven development is a great way to write tests for code because it uses language that humans can understand. Let's see how to implement BDD in Drupal.
In preparation for Agaric's latest migration training, we've seen again that getting a development environment suitable for working on Drupal with Composer is a big road block. For that reason, here are instructions for getting it all going, suitable for our training or for working on Drupal in a code sprint, with only one hard requirement: PHP.
The command line provides so much power. We cover none of that power here, instead showing how to open the door—to open your terminal—on several operating systems.