Books I read (January - April 2014)

January
- Pan, educación, libertad (Ψωμί, παιδεία, ελευθερία), Petros Márkaris
- NW London, Zadie Smith
- 101 cuentos clásicos de la China, Chang Shiru, Ramiro A. Calle
- Mr. Neighborly's Humble Little Ruby Book, Jeremy McAnally

February
- Blankets, Craig Thompson

March
- Practical Object-Oriented Design in Ruby, Sandi Metz
- Modern C++ Programming with Test-Driven Development, Jeff Langr

April
- Learning PHP, MySQL & JavaScript, Robin Nixon
- Measuring the world, Daniel Kehlmann

Interesting Talk: "Test-Driven Development (that’s not what we meant)"

I've just watched this amazing talk by Steve Freeman:

• Test-Driven Development (that’s not what we meant)

These are the talk slides.

Interesting Talk: "Mock Roles Not Object States"

I've just watched this great talk by Nat Pryce and Steve Freeman:

• Mock Roles Not Object States

Interesting Talk: "Exploring a Legacy Clojure Codebase"

I've just watched this interesting talk by Jon Neale and Ragnar Dahlen:

• Exploring a Legacy Clojure Codebase

Interesting Talk: "The SOLID Design Principles Deconstructed"

I've just watched this great talk by Kevlin Henney:

• The SOLID Design Principles Deconstructed

Interesting Talk: "Functional Principles for Object Oriented Development"

I've just watched this interesting talk by Jessica Kerr:

• Functional Principles for Object Oriented Development

This is the Ruby version. There's also a Java version of this talk.

Interesting KataCast: "Clojure TDD demo (Robozzle)"

I've just watched this great explained katacast by Brian Marick

• Clojure TDD demo (Robozzle)

The top-down style Marick uses to grow his code through TDD reminds me a lot of how Gregor Kiczales worked through the example programs in Racket of his Introduction to Systematic Program Design - Part 1 Coursera course that I took a while ago.

The difference between the two processes is basically in the tooling, because Midje allows Marick to "stub" the results of helper functions so he can get feedback about his top functions from the very beginning whereas in Kiczales' examples he had to wait until all the helpers were working to see the top functions tests pass.

Apart from that they use the same top-down approach.

Interesting Talk: "Some Thoughts on Classes After 18 Months of Clojure"

I've just watched this great talk by Brian Marick:

• Some Thoughts on Classes After 18 Months of Clojure

Interesting Talk: "Objects are Just Objects, Aren't they?"

I've just watched this great talk by Rick DeNatale:

• Objects are Just Objects, Aren't they?

Standard Output redirection in Java for a characterization test

Last weekend I did the UglyTrivia legacy code refactoring kata in Java.

Before starting to refactor, I added a characterization test to describe (characterize) the actual behavior of the original code. Since the only "visible effects" of the code were the lines it was writing to the standard output, I had to use that output to create the characterization test.

This is the code of the characterization test:

	package com.adaptionsoft.games.trivia;
	import static org.junit.Assert.assertEquals;
	import java.io.ByteArrayOutputStream;
	import java.util.Random;
	import org.junit.After;
	import org.junit.Before;
	import org.junit.Test;
	import com.adaptionsoft.games.uglytrivia.Board;
	import com.adaptionsoft.games.uglytrivia.Dice;
	import com.adaptionsoft.games.uglytrivia.Game;
	import com.adaptionsoft.games.uglytrivia.Players;
	import com.adaptionsoft.games.uglytrivia.Questions;
	import com.adaptionsoft.games.uglytrivia.Rules;
	public class RunCharacterizationTest {
	StandardOutputRedirection outputRedirection;
	@Before
	public void setUp() {
	outputRedirection = new StandardOutputRedirection(new ByteArrayOutputStream(), System.out);
	}
	@After
	public void tearDown() {
	outputRedirection.reset();
	}
	@Test
	public void gameCharacterizationForSeed1234() {
	Game game = createGame(1234);
	game.run();
	assertEquals(expectedOutput(), outputRedirection.getRedirectedOutput());
	}
	private Game createGame(int seed) {
	Random rand = new Random(seed);
	Game game = new Game(rand,
	new Players("Chet", "Pat", "Sue"),
	new Rules(), new Questions(),
	new Board(), new Dice(rand));
	return game;
	}
	private String expectedOutput() {
	String expectedOutput = "Chet was added\n";
	expectedOutput += "They are player number 1\n";
	expectedOutput += "Pat was added\n";
	expectedOutput += "They are player number 2\n";
	expectedOutput += "Sue was added\n";
	expectedOutput += "They are player number 3\n";
	expectedOutput += "Chet is the current player\n";
	expectedOutput += "They have rolled a 4\n";
	expectedOutput += "Chet's new location is 4\n";
	expectedOutput += "The category is Pop\n";
	expectedOutput += "Pop Question 0\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Chet now has 1 Gold Coins.\n";
	expectedOutput += "Pat is the current player\n";
	expectedOutput += "They have rolled a 4\n";
	expectedOutput += "Pat's new location is 4\n";
	expectedOutput += "The category is Pop\n";
	expectedOutput += "Pop Question 1\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Pat now has 1 Gold Coins.\n";
	expectedOutput += "Sue is the current player\n";
	expectedOutput += "They have rolled a 1\n";
	expectedOutput += "Sue's new location is 1\n";
	expectedOutput += "The category is Science\n";
	expectedOutput += "Science Question 0\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Sue now has 1 Gold Coins.\n";
	expectedOutput += "Chet is the current player\n";
	expectedOutput += "They have rolled a 5\n";
	expectedOutput += "Chet's new location is 9\n";
	expectedOutput += "The category is Science\n";
	expectedOutput += "Science Question 1\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Chet now has 2 Gold Coins.\n";
	expectedOutput += "Pat is the current player\n";
	expectedOutput += "They have rolled a 3\n";
	expectedOutput += "Pat's new location is 7\n";
	expectedOutput += "The category is Rock\n";
	expectedOutput += "Rock Question 0\n";
	expectedOutput += "Question was incorrectly answered\n";
	expectedOutput += "Pat was sent to the penalty box\n";
	expectedOutput += "Sue is the current player\n";
	expectedOutput += "They have rolled a 1\n";
	expectedOutput += "Sue's new location is 2\n";
	expectedOutput += "The category is Sports\n";
	expectedOutput += "Sports Question 0\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Sue now has 2 Gold Coins.\n";
	expectedOutput += "Chet is the current player\n";
	expectedOutput += "They have rolled a 3\n";
	expectedOutput += "Chet's new location is 0\n";
	expectedOutput += "The category is Pop\n";
	expectedOutput += "Pop Question 2\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Chet now has 3 Gold Coins.\n";
	expectedOutput += "Pat is the current player\n";
	expectedOutput += "They have rolled a 5\n";
	expectedOutput += "Pat is getting out of the penalty box\n";
	expectedOutput += "Pat's new location is 0\n";
	expectedOutput += "The category is Pop\n";
	expectedOutput += "Pop Question 3\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Pat now has 2 Gold Coins.\n";
	expectedOutput += "Sue is the current player\n";
	expectedOutput += "They have rolled a 1\n";
	expectedOutput += "Sue's new location is 3\n";
	expectedOutput += "The category is Rock\n";
	expectedOutput += "Rock Question 1\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Sue now has 3 Gold Coins.\n";
	expectedOutput += "Chet is the current player\n";
	expectedOutput += "They have rolled a 3\n";
	expectedOutput += "Chet's new location is 3\n";
	expectedOutput += "The category is Rock\n";
	expectedOutput += "Rock Question 2\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Chet now has 4 Gold Coins.\n";
	expectedOutput += "Pat is the current player\n";
	expectedOutput += "They have rolled a 5\n";
	expectedOutput += "Pat's new location is 5\n";
	expectedOutput += "The category is Science\n";
	expectedOutput += "Science Question 2\n";
	expectedOutput += "Question was incorrectly answered\n";
	expectedOutput += "Pat was sent to the penalty box\n";
	expectedOutput += "Sue is the current player\n";
	expectedOutput += "They have rolled a 3\n";
	expectedOutput += "Sue's new location is 6\n";
	expectedOutput += "The category is Sports\n";
	expectedOutput += "Sports Question 1\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Sue now has 4 Gold Coins.\n";
	expectedOutput += "Chet is the current player\n";
	expectedOutput += "They have rolled a 4\n";
	expectedOutput += "Chet's new location is 7\n";
	expectedOutput += "The category is Rock\n";
	expectedOutput += "Rock Question 3\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Chet now has 5 Gold Coins.\n";
	expectedOutput += "Pat is the current player\n";
	expectedOutput += "They have rolled a 3\n";
	expectedOutput += "Pat is getting out of the penalty box\n";
	expectedOutput += "Pat's new location is 8\n";
	expectedOutput += "The category is Pop\n";
	expectedOutput += "Pop Question 4\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Pat now has 3 Gold Coins.\n";
	expectedOutput += "Sue is the current player\n";
	expectedOutput += "They have rolled a 5\n";
	expectedOutput += "Sue's new location is 11\n";
	expectedOutput += "The category is Rock\n";
	expectedOutput += "Rock Question 4\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Sue now has 5 Gold Coins.\n";
	expectedOutput += "Chet is the current player\n";
	expectedOutput += "They have rolled a 4\n";
	expectedOutput += "Chet's new location is 11\n";
	expectedOutput += "The category is Rock\n";
	expectedOutput += "Rock Question 5\n";
	expectedOutput += "Answer was correct!!!!\n";
	expectedOutput += "Chet now has 6 Gold Coins.\n";
	return expectedOutput;
	}
	}

view raw RunCharacterizationTest.java hosted with ❤ by GitHub

Although in this final version, the expected output reflects the fixing of two bugs in the original code, at the beginning it was just what the original code was writing to the standard output given a fixed seed for the random number generator.

This article describes this technique very well: Working Effectively With Characterization Tests.

To be able to redirect the standard output I used the StandardOutputRedirection class:

	package com.adaptionsoft.games.trivia;
	import java.io.ByteArrayOutputStream;
	import java.io.PrintStream;
	public class StandardOutputRedirection {
	private ByteArrayOutputStream newOut;
	private PrintStream old_out;
	public StandardOutputRedirection(
	ByteArrayOutputStream newOut,
	PrintStream old_out) {
	super();
	this.newOut = newOut;
	this.old_out = old_out;
	System.setOut(new PrintStream(this.newOut));
	}
	public void reset() {
	System.setOut(old_out);
	}
	public String getRedirectedOutput() {
	return new String(newOut.toByteArray());
	}
	}

view raw StandardOutputRedirection.java hosted with ❤ by GitHub

The characterization test shown before yielded a code coverage of 93% which gave me confidence enough to start refactoring the code.

Interesting Talk: "AngularJS in 20ish Minutes"

Yesterday morning I watched this very interesting short talk about AngularJS by Dan Wahlin:

• AngularJS in 20ish Minutes

Kata: UglyTrivia legacy code refactoring kata in Java

I've just solved the UglyTrivia legacy code refactoring kata in Java which was the kata we did in the last Barcelona Software Craftsmanship event.

This is the initial version of the Game class:

	package com.adaptionsoft.games.uglytrivia;
	import java.util.ArrayList;
	import java.util.LinkedList;
	public class Game {
	ArrayList players = new ArrayList();
	int[] places = new int[6];
	int[] purses = new int[6];
	boolean[] inPenaltyBox = new boolean[6];
	LinkedList popQuestions = new LinkedList();
	LinkedList scienceQuestions = new LinkedList();
	LinkedList sportsQuestions = new LinkedList();
	LinkedList rockQuestions = new LinkedList();
	int currentPlayer = 0;
	boolean isGettingOutOfPenaltyBox;
	public Game() {
	for (int i = 0; i < 50; i++) {
	popQuestions.addLast("Pop Question " + i);
	scienceQuestions.addLast(("Science Question " + i));
	sportsQuestions.addLast(("Sports Question " + i));
	rockQuestions.addLast(createRockQuestion(i));
	}
	}
	public String createRockQuestion(int index) {
	return "Rock Question " + index;
	}
	public boolean isPlayable() {
	return (howManyPlayers() >= 2);
	}
	public boolean add(String playerName) {
	players.add(playerName);
	places[howManyPlayers()] = 0;
	purses[howManyPlayers()] = 0;
	inPenaltyBox[howManyPlayers()] = false;
	System.out.println(playerName + " was added");
	System.out.println("They are player number " + players.size());
	return true;
	}
	public int howManyPlayers() {
	return players.size();
	}
	public void roll(int roll) {
	System.out.println(players.get(currentPlayer) + " is the current player");
	System.out.println("They have rolled a " + roll);
	if (inPenaltyBox[currentPlayer]) {
	if (roll % 2 != 0) {
	isGettingOutOfPenaltyBox = true;
	System.out.println(players.get(currentPlayer)
	+ " is getting out of the penalty box");
	places[currentPlayer] = places[currentPlayer] + roll;
	if (places[currentPlayer] > 11)
	places[currentPlayer] = places[currentPlayer] - 12;
	System.out.println(players.get(currentPlayer) + "'s new location is "
	+ places[currentPlayer]);
	System.out.println("The category is " + currentCategory());
	askQuestion();
	} else {
	System.out.println(players.get(currentPlayer)
	+ " is not getting out of the penalty box");
	isGettingOutOfPenaltyBox = false;
	}
	} else {
	places[currentPlayer] = places[currentPlayer] + roll;
	if (places[currentPlayer] > 11)
	places[currentPlayer] = places[currentPlayer] - 12;
	System.out.println(players.get(currentPlayer) + "'s new location is "
	+ places[currentPlayer]);
	System.out.println("The category is " + currentCategory());
	askQuestion();
	}
	}
	private void askQuestion() {
	if (currentCategory() == "Pop")
	System.out.println(popQuestions.removeFirst());
	if (currentCategory() == "Science")
	System.out.println(scienceQuestions.removeFirst());
	if (currentCategory() == "Sports")
	System.out.println(sportsQuestions.removeFirst());
	if (currentCategory() == "Rock")
	System.out.println(rockQuestions.removeFirst());
	}
	private String currentCategory() {
	if (places[currentPlayer] == 0)
	return "Pop";
	if (places[currentPlayer] == 4)
	return "Pop";
	if (places[currentPlayer] == 8)
	return "Pop";
	if (places[currentPlayer] == 1)
	return "Science";
	if (places[currentPlayer] == 5)
	return "Science";
	if (places[currentPlayer] == 9)
	return "Science";
	if (places[currentPlayer] == 2)
	return "Sports";
	if (places[currentPlayer] == 6)
	return "Sports";
	if (places[currentPlayer] == 10)
	return "Sports";
	return "Rock";
	}
	public boolean wasCorrectlyAnswered() {
	if (inPenaltyBox[currentPlayer]) {
	if (isGettingOutOfPenaltyBox) {
	System.out.println("Answer was correct!!!!");
	purses[currentPlayer]++;
	System.out.println(players.get(currentPlayer) + " now has " + purses[currentPlayer]
	+ " Gold Coins.");
	boolean winner = didPlayerWin();
	currentPlayer++;
	if (currentPlayer == players.size())
	currentPlayer = 0;
	return winner;
	} else {
	currentPlayer++;
	if (currentPlayer == players.size())
	currentPlayer = 0;
	return true;
	}
	} else {
	System.out.println("Answer was corrent!!!!");
	purses[currentPlayer]++;
	System.out.println(players.get(currentPlayer) + " now has " + purses[currentPlayer]
	+ " Gold Coins.");
	boolean winner = didPlayerWin();
	currentPlayer++;
	if (currentPlayer == players.size())
	currentPlayer = 0;
	return winner;
	}
	}
	public boolean wrongAnswer() {
	System.out.println("Question was incorrectly answered");
	System.out.println(players.get(currentPlayer) + " was sent to the penalty box");
	inPenaltyBox[currentPlayer] = true;
	currentPlayer++;
	if (currentPlayer == players.size())
	currentPlayer = 0;
	return true;
	}
	private boolean didPlayerWin() {
	return !(purses[currentPlayer] == 6);
	}
	}

view raw GameInitialCode.java hosted with ❤ by GitHub

And this is the code after my refactoring:

	package com.adaptionsoft.games.uglytrivia;
	public class Game {
	private Rules rules;
	private Players players;
	private Player currentPlayer;
	private Turn turn;
	public Game(Players players, Rules rules, Turn turn) {
	this.players = players;
	this.rules = rules;
	this.turn = turn;
	}
	public void run() {
	presentPlayers();
	play();
	}
	private void play() {
	do {
	nextPlayer();
	playTurn();
	} while (noPlayerHasWon());
	}
	private void presentPlayers() {
	int num = 0;
	for (Player player : players) {
	System.out.println(player + " was added");
	System.out.println("They are player number " + String.valueOf(++num));
	}
	}
	private void playTurn() {
	turn.play(currentPlayer);
	}
	private void nextPlayer() {
	currentPlayer = players.next();
	System.out.println(currentPlayer + " is the current player");
	}
	private boolean noPlayerHasWon() {
	return !currentPlayer.hasWonAccordingTo(rules);
	}
	}

view raw GameFinalCode.java hosted with ❤ by GitHub

Update:
And this is the code after I revisited it again (Feb. 27th 2016):

	package com.adaptionsoft.games.uglytrivia;
	public class Game {
	private Rules rules;
	private Players players;
	private Player currentPlayer;
	private Turn turn;
	public Game(Players players, Rules rules, Turn turn) {
	this.players = players;
	this.rules = rules;
	this.turn = turn;
	}
	public void run() {
	do {
	nextPlayer();
	playTurn();
	} while (noPlayerHasWon());
	}
	private void playTurn() {
	turn.play(currentPlayer);
	}
	private void nextPlayer() {
	currentPlayer = players.next();
	}
	private boolean noPlayerHasWon() {
	return !currentPlayer.hasWonAccordingTo(rules);
	}
	}

view raw GameLast.java hosted with ❤ by GitHub

Check my solution in GitHub with commits after each refactoring step.

Interesting Talk: "Testing Online Crazy Glue: Strategies for building testable PHP applications"

I've just watched this interesting talk by Chris Hartjes:

• Testing Online Crazy Glue: Strategies for building testable PHP applications

Introduced FormEmailService façade and struggling with names again

Following the advice given by One on a comment, I introduced a façade service that encapsulate everything about emails, FormEmailService with FormEmailComposer and EmailSender as collaborators. This simplified the creation of the IntroducedInformation class which was great.

I also followed his suggestion of passing the form object as a parameter to the sendByEmailAndRedirect method.

This was how it was used after that change:

	<?php
	$info =
	IntroducedInfoBuilder::aNewIntroducedInformation()
	->onPage("empresas")
	->toBeSentTo("xxx@ppp.es")
	->build();
	$info->sendByEmailAndRedirect(new Form($_POST));

view raw otherUse.php hosted with ❤ by GitHub

Although the creation of the IntroducedInformation got simpler, I didn't like how it read anymore because an "information thing" was now sending a form.

In the previous version the "information thing" was sending itself using a "Yoda-like" language:

	<?php
	$info =
	IntroducedInfoBuilder::aNewIntroducedInformation()
	->onPage("empresas")
	->toBeSentTo("xxx@ppp.es")
	->build();
	$info->sendByEmailAndRedirect();

view raw use3.php hosted with ❤ by GitHub

To keep the form as a parameter I decided to rename the class to so it was "something that does something on something" and not finding any better name I went down the road of "SomethingService" names:

	<?php
	$service =
	EmailAndRedirectServiceBuilder::aServiceToSendByEmail()
	->aFormOnPage("empresas")
	->to("xxx@ppp.es")
	->build();
	$service->sendAndRedirect(new Form($_POST));

view raw use4.php hosted with ❤ by GitHub

Well, it's not perfect but at least I think it reads better than the version where the "information thing" was sending a form.

This is how the class looks now:

	<?php
	class EmailAndRedirectService
	{
	private $redirection;
	private $emailService;
	function __construct(
	FormEmailService $emailService,
	Redirection $redirection
	) {
	$this->emailService = $emailService;
	$this->redirection = $redirection;
	}
	public function sendAndRedirect($form)
	{
	if ($form->isNotFilled()) {
	$this->redirection->backToInitialPage();
	return;
	}
	$email = $this->createEmail($form);
	$sendingSucceeded = $this->send($email);
	$this->redirect($sendingSucceeded);
	}
	private function redirect($sendingSucceeded)
	{
	if ($sendingSucceeded) {
	$this->redirection->toSuccessPage();
	} else {
	$this->redirection->toFailPage();
	}
	}
	private function createEmail($form)
	{
	return $this->emailService->composeEmailFrom($form);
	}
	private function send(Email $email)
	{
	return $this->emailService->send($email);
	}
	}

view raw EmailAndRedirectService.php hosted with ❤ by GitHub

and these are its tests:

	<?php
	class EmailAndRedirectServiceTest extends PHPUnit_Framework_TestCase
	{
	private $form;
	private $redirection;
	private $emailAndRedirectService;
	private $email;
	private $formEmailService;
	function setUp()
	{
	$this->redirection = Phake::mock('Redirection');
	$this->email = new Email("from", "to", "subject", "message");
	$this->form = Phake::mock('Form');
	$this->formEmailService = Phake::mock('FormEmailService');
	$this->emailAndRedirectService =
	new EmailAndRedirectService(
	$this->formEmailService,
	$this->redirection
	);
	}
	function testRedirectionBackToFormPage()
	{
	$this->whenFormNotFilled();
	$this->emailAndRedirectService->sendAndRedirect($this->form);
	Phake::verify($this->redirection)
	->backToInitialPage();
	}
	function testEmailComposition()
	{
	$this->whenFormFilledWithWhateverFields();
	$this->andEmailGetsComposed();
	$this->emailAndRedirectService->sendAndRedirect($this->form);
	Phake::verify($this->formEmailService)
	->composeEmailFrom($this->form);
	}
	function testEmailSending()
	{
	$this->whenFormFilledWithWhateverFields();
	$this->andEmailGetsComposed();
	$this->emailAndRedirectService->sendAndRedirect($this->form);
	Phake::verify($this->formEmailService)
	->send($this->email);
	}
	function testRedirectionToSuccesPage()
	{
	$this->whenFormFilledWithWhateverFields();
	$this->andEmailGetsComposed();
	$this->andIsSentSuccessfully();
	$this->emailAndRedirectService->sendAndRedirect($this->form);
	Phake::verify($this->redirection)->toSuccessPage();
	}
	function testRedirectionToFailPage()
	{
	$this->whenFormFilledWithWhateverFields();
	$this->andEmailGetsComposed();
	$this->butIsNotSentSuccessfully();
	$this->emailAndRedirectService->sendAndRedirect($this->form);
	Phake::verify($this->redirection)->toFailPage();
	}
	private function whenFormFilledWithWhateverFields()
	{
	Phake::when($this->form)
	->isNotFilled()
	->thenReturn(false);
	}
	private function whenFormNotFilled()
	{
	Phake::when($this->form)
	->isNotFilled()
	->thenReturn(true);
	}
	private function andIsSentSuccessfully()
	{
	Phake::when($this->formEmailService)
	->send($this->email)
	->thenReturn(true);
	}
	private function butIsNotSentSuccessfully()
	{
	Phake::when($this->formEmailService)
	->send($this->email)
	->thenReturn(false);
	}
	private function andEmailGetsComposed()
	{
	Phake::when($this->formEmailService)
	->composeEmailFrom($this->form)
	->thenReturn($this->email);
	}
	}

view raw EmailAndRedirectServiceTest.php hosted with ❤ by GitHub

I keep thinking in a name for this that doesn't follow the "SomethingService" pattern, but until inspiration comes I'll settle on this one.

Thank you very much Carlos, Marcin and José for your feedback. I really appreciate it.