Practicing AdvancedUnit Testing

v2.3.2 (13.04.2023)

with the«Trading Card Game»

Kata

Battlecry: Draw a slide.Deathrattle: Transformaudience into 1/1 sheep.

Speaker

Kata

Kata ( 型 or 形 literally: "form”) is a Japanese word describing detailed

choreographed patterns of movements practiced either solo or in pairs.

Trading Card Game (TCG)

A […] trading card game (TCG) […] is a card game that uses specially designed sets of playing cards […] mass-produced for trading or 

collectibility, and it must have rules for strategic game play. Acquiring these cards may be done by trading with other players or buying card 

packs.

Why invent another Kata?

Bro, why U not use

?????

Rules not extensible

Not TDD-friendly

Too easy

Hearthstone: Heroes of Warcraft®

Kata Trading Card Game

Player Setup

0 0 1 2 2 2 3 3

3 4 4 4 5 6 6 7 8

30 0/0

Health ManaD

eck

1 3

5

Hand

2

7

Active Player

1 3 5

8

0/11/1

Gameplay

2

30 300/0

3Play Card 1

29

Cause 1

Damage

0/0

Draw Card

-1

Receive +1

Mana Slot

Replenish

ManaPay 1

Mana

Game Table

Draw extra Card

2 4

0/1

Forced Turn Skip

25 8

30 1/1

23

29

3

No affordable Cards

2/2

7

29

4

0/2

Ongoing Gameplay

25 8

30 1/1

23

27

3 4

2

2

-2

2/2

7

12

4

8/8

Overload Rule

75 8

18 7/7

8016

2

Discard Card when Hand

already holds 5 Cards 7

410/10

Mana Cap

5

8 10/10

166 Mana is capped at 10 Slots

410/10

Bleedout Rule

5

8 10/10

166Drawing

from empty Deck

7-1

Cause 1

Damage

410/10

Game End

5

10/10

166

7 -2-6

Winner! Loser!

4/10

Kata TCG Rules & Variations

https://github.com/bkimminich/kata-tcg

Detailed rules descriptionAdvanced Variations

Healing cardsUse cards as MinionsDifferent cost & damageCard drawer cardsDeck customization

Kata TCG Sample Solution in Java

https://github.com/bkimminich/kata-tcg

Java 8Lambdas & Stream API

JunitMockito

For handling dependencies of tested objects

HamcrestMatchers for better legibility in assertions

System RulesJUnit @Rules for substituting java.lang.System

Other Sample Solutions

https://github.com/bkimminich/kata-tcg

GroovySpock

JavaScriptKarmaJasminePhantomJS

Advanced Unit TestingExamples

Skip No-Brainers

…

Compile Error as Red Test

Red

Green

Refactor

Obvious Implementation

Simplest possible

step

Simplest useful step

Specify the Object under Test

Irrelevant Details

Setter introduced for

testing

Implementation Detail

Assuming Hidden Default

Define the Object under Test

Another unwanted

setter

Hidden default problem solved

Builder Pattern

Reads like natural

language

Explicitly listed Expectations

No unnecessary details

…?

Builder Internals

Sensible Default Values

Package visible full Constructor

needed

Fluent API

Setting properties via

fluent API

Mocking Behavior

Interface has no implementation

yet

Mock Behavior for

this Test

Trashcan RefactoringCardPicker turned

out to be overengineered

Mocking

Mocking BDD Style

Can beconfused withGiven-When-

Then part

Can beconfused withGiven-When-Then part

Mocking BDD Style

Sugar coating for BDD syntax

Matches its meaning inGiven-When-Then

structure

Avoid Redundancy

Redundant & spoiled with Implementation

Details

Another slight redundancy

Avoid Constants

Disturbs the reading flow

Syntactic Sugar

Improves Legibility and

removes Redundancy

More Syntactic Sugar

Magic Number

sDifferent Level of Abstraction

Syntactic Artificial Sweetener

No-Op SyntacticSugar for Legibility

Syntactic Sugar

reduces Redundancy

Test DiabetesToo much Sugar is bad for your

Test

Customer Matchers can medicate this

Custom MatcherEncapsulation of

Expectation

Produces helpful Error

Messages

Even better with just a little bit of

Sugar

Demo | Q&A

Demo: Test Execution

All tests passPretty fast

Demo: Code Coverage

Ugly UIUgly Retro UI

Demo: Human vs. AI Game

Player Inputvia System.in

AI beats me! Again!

Thank you for your attention!

Recording of this talk at „Agile Saturday X“ in Tallinn, Estoniahttps://vimeo.com/92886146

https://twitter.com/bkimminichhttps://linkedin.com/in/bkimminichhttps://google.com/+BjörnKimminichhttp://slideshare.net/BjrnKimminich/

Credits

Background Image: Demonplay (Permission of

use granted)

Other Images:Blizzard Entertainment (Permission of use requested)

Wikipedia, Github, Agile EstoniaAllmystery.de, Gueball.de, Natekohl.net,

Scenicreflections.com

Hearthstone: Heroes of Warcraft® is a trademark or registered trademark of Blizzard Entertainment, Inc., in the U.S. and/or other countries.