AOTB2014: Agile Testing on the Java Platform

Agile TESTING Practices ON THE Java Platform Creative development in principle Peter Pilgrim Scala and Java EE Independent contractor @peter_pilgrim uk.linkedin.com/in/peterpilgrim2000/

Creative Commons 2.0 Attribution-NonCommercial-ShareAlike 2.0 UK: England & Wales (CC BY-NC-SA 2.0 UK) https://creativecommons.org/licenses/by-nc-sa/2.0/uk/ • Share — copy and redistribute the material in any medium or format • Adapt — remix, transform, and build upon the material • The licensor cannot revoke these freedoms as long as you follow the license terms. Xenonique 2

Xenonique About Me • Scala and Java EE developer independent contractor • Digital transformation GOV.UK • Java Champion • Working on the JVM since 1998 3

Xenonique Java EE 7 Developer Handbook September 2013 Packt Publishing Digital Java EE 7 Web APPS December 2014 4

Xenonique 5 • TDD • Java Technology • Creative Development in Principle • Scala Technology

Xenonique Is TDD Dead? • TDD is Dead, Long Live Testing Blog article by David Heinemeier Hanson http://david.heinemeierhansson.com/2014/tdd-is-dead-long-live- testing.html • Series of 5 Google Hangout Videos @dhh, @kentbeck and @martinfowler http://martinfowler.com/articles/is-tdd-dead/ 8

Xenonique 9 “I rarely unit test in the traditional sense of the word, where all dependencies are mocked out, and thousands of tests can close in seconds. It just hasn't been a useful way of dealing with the testing of Rails applications.” D.H.H

Xenonique 11 JUnit the mother of all unit tesFng frameworks

Xenonique 12 #1 Java unit testing framework on the JVM. Other alternate languages have variants or interoperability.

Xenonique 13 2007 JUnit 4.4 XMLUnit, DBTest, HTMLUnit, PerfTest, EasyMock, Test NG, Cactus, SoapUI

Xenonique 14 2014 - JUnit 4.12? Mockito, Concordion, Spring, JMock, Arquillian, Fit/Fitnesse, JBehave, ScalaTest, Spock

JUnit Test Example #1 import org.junit.*; import static org.junit.Assert.assertThat; import static org.hamcrest.CoreMatchers.*; public class ForexTradingDeskTest { TradingDesk desk = Xenonique new ForexTradingDesk(); /* ... */ } 15

JUnit Test Example #2 public class ForexTradingDeskTest { @Before public void setUp() { Xenonique desk.acquire(); } @After public void tearDown() { desk.release(); } /* ... */ } 16

Java Test Example #3 @Test public void shouldExecuteTrade() { Trade trade = ForexTrade("GBP","EUR", 10000); desk.execute(trade); assertThat( trade.getStatus(), Xenonique is(Executed)); } 17

Xenonique 20 These tools were built for the mother language of the Java Virtual Machine.

Xenonique 21 Sadly, these tools do not work too with:

Three development concepts for agile digital applications Xenonique 23 Efficiency Design Human Nature

Xenonique 24 #1 Understanding the Efficiency of our Java application development

30.7% Github projects* have a dependency on JUnit. Yet we, Java developers, still write too much boilerplate, over-engineer design patterns. We forget about directing the future. *http://www.takipiblog.com/we-analyzed-30000-github-projects-here-are-the-top-100-libraries-in-java-js-and-ruby/ Xenonique 25

Xenonique 26 Hard-‐coded dependencies and unassailable fixtures are the issues. It does not maNer which technology.

Java is a programming language. Java is a virtual machine. Java is a platform. Xenonique 27 Technology is not the problem. How much do we understand design and architecture?

Xenonique 28 #1 Completeness: As digital transformation engineers, what would happen to admitted: we can never have 100% coverage complete with just unit-tests? What are we measuring? How are we measuring? Impossible to prove all branches in a program

Xenonique 29 #1 Efficiency: Prefer to write tests than none at all Prefer to mock out dependencies Prefer to test the simplest thing possible Avoid duplication (cut and paste tests) Reduce fixtures and preconditions

#1 Efficiency: Prefer integration tests over unit tests. Remove unit tests that over time are always ”green”. Rely on functional and acceptance tests as well. Xenonique 30 Hire a developer-in-test into your team Avoid being a unit-test automaton.

Xenonique 31 #2 The age-old issue of how do we Design? Time, space and cost are constants

Xenonique 32 “TEX would have been a complete failure if I had merely specified it and not participated fully in its initial implementation. The process of implementation constantly led me to unanticipated questions and to new insights about how the original specifications could be improved.” Donald Knuth

Xenonique 33 #2 Design Test-‐First may be harmful True design presupposes we have ability to escape restric@ons. It requires to innovate around the architectural boundaries. Edit -‐> Compile -‐> Test -‐> Refactor

Xenonique 34 #2 Design Our problem is abstrac@on “Debugging is not what you do when you fire up the debugger. It is when you lie back in the chair and look at the ceiling.” Crea@vity is a thought process

Xenonique 35 #2 Design – Problem solving versus art Balance crea@vity whilst respecFng produc@vity and testability

Xenonique 36 #2 Design – search the Internet for a video Bret Victor, Inven@ng on Principle

Xenonique 37 #3 Human Nature It’s always about the folk. How long did it take to learn this simple truth in computer science?

Xenonique 38 #3 Human Nature Now it is about everyone on the planet We are serving the digital customers for all the screens of our lives

Xenonique 39 #3 Human Nature Developers require UX education. We cannot afford to not invest in learning. Digital transformation is open for all people.

Xenonique 40 #3 Human Nature “He said it was more important that the company avoid the appearance of having done something wrong than that we stop before producing an incorrect result. I left the company.“ Jim Coplien, Why Unit Testing is a Waste hNp://www.rbcs-‐us.com/documents/Why-‐Most-‐Unit-‐TesFng-‐is-‐Waste.pdf

#3 Human Nature Good developers are generally good writers. Great developers can create AM #1: “Interactions and individuals over processes and tools” Xenonique 41

Xenonique Scala Test #1 import collection.mutable.Stack import org.scalatest._ class StackSpec extends FlatSpec with Matchers { /* ... */ } 43

Xenonique Scala Test #2 class StackSpec extends FlatSpec with Matchers { "A Stack" should "pop values in last-in-first-out order" in { val stack = new Stack[Int] stack.push(1) stack.push(2) stack.pop() should be (2) stack.pop() should be (1) } /* ... */ } 44

Xenonique Scala Test #3 class StackSpec extends FlatSpec with Matchers { /* ... */ it should "throw NoSuchElementException if an empty stack is popped" in { val emptyStack = new Stack[Int] a [NoSuchElementException] should be thrownBy { emptyStack.pop() } } } 45

How to avoid null pointers in Xenonique Scala Programming? val greeting1: Option[String] = Some("AOTB14") val greeting2: Option[String] = None 46

Xenonique Pattern Matching def checker(p : Option[String]): String = { p match { case Some(v) => v case _ => "Unexpected" } } checker(greeting1) // "Hello AOTB14" checker(greeting2) // "Unspecified" 47

Scala’s generic immutable list Xenonique collection type val list: List[Int] = List(1,2,3,4) list.foreach { x => println(x) } // 1,2,3,4 48

Scala’s option behaves like Xenonique collection type #2 greeting1.foreach { x => println(s"Work: ${x}" ) } // Work: Hello AOTB14 greeting2.foreach { x => println(s"Work: ${x}" ) } // *** nothing happens *** 49

Read, Evaluate, Print, Loop • Scala, Clojure, Groovy, Kotlin, Ceylon, Fantom All have a interpretative mode • Java JDK does not (yet) have an official REPL (However try out javarepl.com online) • Fingers crossed Project Kulla in JDK 9 http://blog.gmane.org/gmane.comp.java.openjdk.general Xenonique 50

Xenonique 51 #DailyWork2014 GOV.UK • Develop Scala applications • Play Framework, RESTful Services, MongoDB • Cucumber testing: acceptance & functional • Collaborative design, pairing and reviews • SCRUM, Sometimes Kanban • Physical storyboards, retros, planning • Heavy dose of UX / User Centric • Government Digital Service

Xenonique 52 • TDD • Java Technology • Creative Development in Principle • Scala Technology

Xenonique Recipe for Success • Be creative and artistic again • Leave a digital legacy of achievement • Be efficient, evolve design and aware of human nature • Invent your own principles 54

Xenonique 55 @peter_pilgrim uk.linkedin.com/in/peterpilgrim2000/

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List of Creative Commons (2.0) photography attributions https://www.flickr.com/photos/code_martial/ https://flic.kr/p/7jmU5n Tahir Hashmi Follow Developer Death 10 Programmers and a UX Designer died all of a sudden in a war room situation. They were apparently working too hard. https://www.flickr.com/photos/8268882@N06/ https://flic.kr/p/duwd1M Peter Pilgrim IMG_1481 European JUG leaders meeting in Devoxx 2013 https://www.flickr.com/photos/unicefethiopia/ https://flic.kr/p/dv4ooi UNICEF Ethiopia Follow Hamer mother and child South Omo Zone, SNNPR Hamer mother and child South Omo Zone, SNNPR. ©UNICEF Ethiopia/2005/Getachew Xenonique 57

List of Creative Commons (2.0) photography attributions https://www.flickr.com/photos/15216811@N06/ https://flic.kr/p/baULpM N i c o l a Follow Tree - IMG_1242 https://flic.kr/p/dwCQ7t https://www.flickr.com/photos/90585146@N08/ marsmetn tallahassee Follow IDA .. Integro-Differential Analyzer (Sept., 1952) ...item 2.. Richard Dreyfuss: Technology Has 'Killed Time' -- "In geopolitics, the removal of time is fatal." -- "And you will give up, the protection of Republican Democracy." (July 19 2010) ... https://flic.kr/p/6ZDbiZ https://www.flickr.com/photos/ingmar/ Ingmar Zahorsky Follow Traffic Jam Accidents are common on the narrow streets going through the mountains of Nepal. When such an accident occurs, traffic is often halted for up to 3-4 hours. https://flic.kr/p/opvVsg https://www.flickr.com/photos/gregbeatty/ Greg Beatty Follow Three Pillars Nikon D800 16-35MM F4.0 https://flic.kr/p/FAskC https://www.flickr.com/photos/mari1008/ mari_1008 Follow traffic jam -B Date: April,2th Address: Jiangshu Rd,Shanghai,China. Around 8:30 AM today, A little accident on YuYuan Rd and JiangSu Rd caused traffic jam. Xenonique 58

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