What is TDD & BDD and how do they differ? 

Good responses =

• TDD stands for Test Driven Development, BDD stands for Behaviour Driven Development. 
• TDD is a way to determine that small sections of code are returning the expected results by writing tests up front that that match the required outcomes. Examples of this are Unit Testing, Integration Testing and Behavioural Testing (Bonus points if PHPUnit Selenium, Mink or Codeception are mentioned). 
• BDD focus on testing the business behaviour of the application regardless of the underlying code. BDD Tests generally test a user flow through an application, rather than sections of code. (Bonus points if Behat, Selenium, Cucumber, Gherkin, Codeception or PHPSpec are mentioned)