TDD workshop

Agenda

  • Hello World
  • Benefits of TDD
  • Code coverage
  • Roman Numerals Kata
  • Zodiac app
  • ETA Detroit app

Hello World

Lab 1 - Hello World

1. Open Xcode
2. Make sure Xcode is 8.x
3. Open Main.storyboard
4. Search for TextView in the Object Library
5. Drag over to Storyboard
6. Run

Lab 2 - Hello World

1. Open Terminal
2. cd /path/to/HelloWorld
3. Run the command

    xcodebuild build -project HelloWorld.xcodeproj 
        -scheme HelloWorld 
        -destination 'platform=iOS Simulator,name=iPhone 7 Plus'

Test Driven Development

Test Driven Development

  • Write test first
  • See it fail
  • Write simplest possible solution to get test to pass
  • Refactor
  • Wash, Rinse, Repeat 

Uncle Bob's Rules

  • You are not allowed to write any production code unless it is to pass a failing unit test

 

  • You are not allowed to write any more of a unit test than is sufficient to fail, and compilation failures are failures

 

  • You are not allowed to write any more production code than is sufficient to pass the one failing unit test

Test Driven Development

  • Built in regression testing
  • Longer life for your codebase 
  • YAGNI feature development
  • Red/Green/Refactor helps kill procrastination

TDD

You can't TDD w/o unit testing

TDD means writing the tests before the code

TDD is more painless than classic unit testing

Unit Testing

You can unit test w/o TDD

Unit tests don't mandate when you write the tests

Unit tests are often written at the end of a coding cycle

Lab 3 - Hello World TDD

Features

- User gets valid result when
  dividing divisor by dividend 

- User can not divide by zero

Lab 3 - Hello World TDD

1. Create Xcode project called Division
2. Add two text fields, divide and results label and button
3. Create IBoutlets, IBActions 
4. Create Calculator object
5. Create Unit test for feature 1
6. Run test - test will fail
7. Fix Calculator code so test passes
8. Create Unit test for feature 2
9. Run test - test will fail
10. Fix Calculator code so test passes
11. Run test
12. Refactor - fix ViewController code
13. Turn on code coverage
14. View code coverage

XCode TDD

XCode TDD

Exercism Kata

Exercism Kata

Write a function to convert from Arabic numbers to Roman Numerals

Write a function to convert from Roman Numerals to Arabic numbers

Exercism Kata

1. Create ArabicToRoman project in Xcode
2. Check Unit Tests
3. Open ArabicToRomanTests - use the two screens in Xcode
4. Create ArabicToRomanModel.swift 
5. Create toRoman stub function
6. Create testConvertToRoman test
7. Run test from command line, test will fail
8. Fix toRoman stub function
9. Run test from command line, test passes
10. Refactor
11. Repeat for second feature

XCode TDD

Sample App

Feature 1 - Display list of Zodiac Signs

Feature 2 - Display descriptions of Sign

Feature 3 - Display daily horoscope

Sample App

Resource

https://medium.com/@ynzc/getting-started-with-tdd-in-swift-2fab3e07204b

https://github.com/samantha-wong/FizzBuzz

https://gist.github.com/kumo/472043819fec7a3737f8

https://github.com/pigmonchu/TDDiOS

http://rshankar.com/test-driven-development-in-swift/

TDD workshop

By godfreynolan

TDD workshop

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