TDD
WORKSHOP

80 minutes · 3-Way Ping-Pong · Hands-on Practice

The TDD Rhythm

1

Red

Write failing test

→

2

Green

Make it pass

→

3

Refactor

Clean up code

→

↻

Repeat

Next test

80

Today's Schedule

0:00

Welcome & Setup

5 minutes · Verify environment

0:05

Live Demo: FizzBuzz

15 minutes · Watch TDD in action

0:20

Exercise Intro

5 minutes · 3-Way Ping-Pong explained

0:25

Hands-on Practice

40 minutes · Mob programming

1:05

Retrospective

15 minutes · Reflect & discuss

3-Way Ping-Pong

A

Red

Uncomment test
Watch it fail

→

B

Green

Write minimal code
Make it pass

→

C

Refactor

Clean up
Next test

Rotate roles with each cycle · One shared screen

RED Phase

Write a failing test

Uncomment ONE test
Run dart test
Watch it fail (proves it can fail)
Pass the keyboard

          // Uncomment this test

          test('returns 1 for input 1', () {

            expect(fizzbuzz(1), '1');

          });

GREEN Phase

Make it pass (minimal code)

Write the simplest code that works
Don't worry about perfection
Run tests to confirm GREEN
Pass the keyboard

          String fizzbuzz(int n) {

            return '1'; // Hardcode is OK!

          }

REFACTOR Phase

Clean up the code

Remove duplication
Improve names
Tests stay GREEN
Uncomment next test (back to RED)
Pass the keyboard

Choose Your Kata

Password Validator

Rules-based validation · Refactoring challenge · Open-Closed Principle

Shopping Cart

Stateful domain object · Data structures · Value Objects

TDD Principles

Tests first — Even for "obvious" code
Small steps — One test at a time
See RED — Proves the test can fail
Minimal GREEN — Hardcoding is OK initially
Refactor fearlessly — Tests protect you

Ready to
Practice?

Let's build muscle memory for TDD

TDD WORKSHOP