TDDTest Driven Development

Clean code that works

Two Rules

• Don’t write a single line of code unless you have a failing automated test

• Eliminate duplication

Write a little test

Make the test work (quick and dirty)

Eliminate all duplication (Refactor)

Red/Green/Refactor

Why this rocks..

• Reduces defect density

• Reduces risk

• Interaction between developers

• Shippable software === Agile

Fear

Cups of Coffee Per Cup Total

Starbucks 25 4 100

Total 100

Cups of Coffee Per Cup Total

Starbucks 25 S$ 4 S$ 100

Highlands 15 VND 25,000 VND 375,000

Total ???

Cups of Coffee Per Cup Total

Starbucks 25 S$ 4 S$ 100

Highlands 15 VND 25,000 VND 375,000

Total S$ 125

SGD/VND 15,000

7 USD +10 SGD = 14 USD(if SGD to USD = 0.7)

7 USD x 2 = 14 USDlet’s start small

7 USD x 2 = undefinedoh boy …

7 USD x 2 = 14 USDbut wait …

this.amount = 7 * 2dependency —> duplication