9. build a retail calculator
• build a retail calculator in 40 minutes, divided in 5
iterations of 8 minutes each
• split our use case in 15 to 20 user stories (most
people will build this in 2-3 slices, not our case!)
• a story is only valid if it has a UI, input & output,
and is visible different from the last story
• every story should be elephant-shaped, together
the form the whole elephant
11. priorities
target is: 5 discounts, 5 states
5 states before doing anything
with discounts (why? we can deploy!)
validation and fancy gui at the end!
12. hints
• stories:
• implementable in 2-6 minutes
• different from previous story
• more value to customer than the previous story
• no story is just a mockup, UI, test case e.t.chard co
• your first slice? anything bigger than hello world is too big!
• discuss value of quickly building your walking skeleton (key architectural
components)
• next slices? no state, no discounts, hard coded taxes, two letter states, how
many states, discounts, tests e.t.c
13. review
• how far did you get on the value curve?
• how many stories?
• Acceptance tests:
• i am in california, and i am buying 65535 items,
and each one cost 123.45$. the total amount i
have to pay?
14. review
• how far did you get on the value curve?
• how many stories?
• Acceptance tests:
• i am in california, and i am buying 65535 items,
and each one cost 123.45$. the total amount i
have to pay?