H1 - agile

TDD comes under extreme programming (XP), and therefore agile

traditionally, the software design process was borrowed from engineering:

• create a detailed blueprint
• build
• test
• release

agile rejects 'Big Design Up Front', and focuses on continuous releases

the issues with agile:

XP practices:

• test-driven development
• pair programming
• continuous integration
• small releases
• on-site customer
• refactoring
• collective code ownership
• 40-hour week

it is an iterative design where planning and building are unified