Techniques for capturing business requirements. Keywords: flowchart, diagrams, business process, sequence diagram, module diagram, analysis. This is presented in Inno Tech Bootcamp 2 on 5th July 2018. #itbc2

1. Lazy
Programmer’s
Guide To Writing
Spec
Inno Tech Boot Camp 2018 July #ITBC2
Leong Hean Hong

2. Agenda
● Purpose
● Feature List
● Business Process
● Business Rule
● Other Diagrams
● API Spec

4. Why Should I Write Spec?
● Confirm what user wants
● Make sure we are developing the right software
● Clarity among team members
● Ensure members work toward same direction
Tip: Do not write something nobody reads

5. Guideline
● Start from high level, go more detail as you need
● If not sure need to write or not, write anywhere
● Be as specific as possible
● Prefer image over words
● Make it easy to read & understand
● Assume reader of spec document is confused, with no prior knowledge of this project

6. Let’s build
an eWallet!

7. Feature List

9. Functional vs Nonfunctional
Requirements
● Functional Requirements - that is of value to user
● Nonfunctional Requirements - user don’t care

10. Functional Requirements
● An user can transfer money to another user
● User can topup wallet using different payment methods (Credit Card, IB, scratch card)
● User can check balance
● User can receive money by sending URL link to payer
● User can transfer money by scanning QR code

11. Nonfunctional Requirements
● Network communication must be secured (HTTPS)
● Compliance with KYC, AML/CFT
● It need to support at least 200 concurrent transactions
● Log all transactions
● Daily reconcile

12. Business Processes

14. Business Process
● Sequence of actions user performs to achieve an objective.
● User can be human or system
● Example of objective
○ Scan QR code to make payment
○ Generate and send payment link
● Method
○ Writing
○ Flowchart
○ Sequence Diagram

15. Example: Writing
1. Merchant use system to generate QR code.
2. Merchant print and display QR code.
3. Payer scan QR code.
4. Payer types in payment amount.
5. Payer confirms payment with 6-digits PIN.

16. Method: Writing
● Clearly define actors (“who”) and actions (“what”)
● Hard to express if/else, loop
● Wordy

17. Example: Flowchart

18. Method: Flowchart
● Can express if/else, loop
● Take up large space
● Flow chart symbols: http://bit.ly/2zanyxb
○ Start/end
○ Process
○ Display
○ Decision
● Lack of actor information

19. Example: Sequence Diagram

20. Method: Sequence Diagram
● Clearly define actors and actions
● Hard to express if/else, loop
● Shows interactions between multiple actors
● Sequence from top to bottom

21. Business Rules

23. Business Rules
● Imagine “if/else” and “switch” for business.
● Make decision based on conditions/criteria

24. Business Rule Example (1)
Amount < $50.00 Amount ≥ $50.00
ID Verified Y Y
ID Not Yet Verified Y N
Rules for allowing transfer:

25. Business Rule Example (2)
Topup Amount Reward
< $50 1%
$50.00 ~ $99.99 2%
$100.00 ~ $199.99 3%
≥ $200.00 4%

26. Other Diagrams

27. System Diagram

28. System Diagram
● High-level concept
● Relationship between different (sub)systems

29. Module Diagram

30. Module Diagram
● Dependency: top depend on bottom
● Composition: module contain submodules

31. Relationship Diagram

32. Relationship Diagram
● Different from entity-relationship diagram
● Good for showing high-level concepts
● Describes relationships
● May not be direct reflection of DB schema

33. API Spec

34. API Spec
● Test/Production URLs
● Authentication (e.g. Token, HTTP Basic Auth)
● Listing of each endpoint
○ Brief description
○ List all parameter (name, data type, optional?, description, data size, values)
○ Example request
○ Example response
Reference:
● Xpressify, Mailgun

35. Ending Note
● Inspired by UML Diagrams (highly recommend you read up on it http://bfy.tw/5dZO)
○ Class Diagram
○ Activity Diagram
○ Sequence Diagram
○ State Machine Diagram