Diamond Age

diamondage

Let's learn about via these 46 free stories. They are ordered by most time reading created on HackerNoon. Visit the to find the most read stories about any technology. Pokemon /Learn Repo 1. 5 Nintendo Switch Games Coming Soon in 2021/2022 There are great games on the horizon, but these Nintendo Switch games coming soon are what I'm excited for. 2. Mawile in Pokémon Sword: How to Find it and Catch it Mawile in Pokémon Sword can be found in the wild area, dens, and the Crown Tundra. You will need fire and ground type Pokemon as well as high-level items 3. The Top Yikes of Pokémon Scarlet and Violet Poor performance and lazy pokemon design in Pokemon Scarlet and Violet are among the top complaints from diehard fans of the franchise. 4. Top 10 Pokémon Characters Fans Love Pokémon has had loads of iconic and memorable characters over its 25 years. Do you want to know the 10 characters that fans love the most? Let's find out. 5. Will the Next New Pokémon Game be a Diamond and Pearl Remake? Fans have speculated that the next new Pokemon game could be a Pokemon Diamond and Pearl remake, based on historical trends in the company's release cycle. 6. 10 Best Nintendo 3DS Games of all Time Ranked by Sales To name a few, the best 3DS games such as Mario Kart 7 and Pokemon have helped the 3DS  to sell huge numbers of hardware and software. 7. Teddiursa: A Deep Dive into Pokemon’s Most Important Bear Teddiursa debuted in Pokemon Gold & Silver, but has since become a background character. Here's why the bear Pokemon is important. 8. How to Use PKHex On Switch to Mod Pokemon Scarlet & Violet Here's how to use PKHex on the Nintendo Switch to edit what Pokemon are in your party. 9. Where to Sell Pokémon Cards Online: 3 Options To sell Pokemon cards online, you can sell your Pokemon cards on eBay as well as to collectors, and professional toy auctions. 10. The Digital Evolution of the Collecting Sector Collecting is part of human nature. Since the times of Roman generals who exhibited the trophies collected during the war campaigns in their homes. 11. Pokémon Natures: Everything You Need To Know In this comprehensive guide we will break down the 25 Natures and their effects so you can work them into your Pokémon strategy. 12. One Day in Paldea: A Review of Pokemon Scarlet and Violet Despite some persistent graphical glitches, the new Pokemon Scarlet and Violet successfully expand on the open world concept brought in by Legends: Arceus. 13. What is your favorite video game movie? Video game movies have earned a reputation for being less than stellar, but are there any good ones? 14. At the Metaverse Frontier – Redefining the Future of Play-To-Earn, and Integrating E-Sports in Block Josh Wilson's concept of Sacred Tails illustrates how we might consider gaming as a method to make money while having fun. 15. Pokémon Radical Red: The Perfect Reimagining of a Classic Pokémon Radical Red is one of the best Pokémon ROM hacks available and should be played by any franchise fan. 16. 5 Best Pokémon Games of All Time Ranked Pokémon's 25th anniversary is this week. To celebrate its anniversary, here are the top 5 best Pokémon games of all time. 17. 10 Best GBA Games of All Time Ranked by Sales The best GBA games, such as Pokémon and Mario, have helped the console shift units. Pokemon Ruby and Sapphire are the best selling GBA games alongside others. 18. 10 Best Pokémon ROM Hacks You Can Download for Free ROM's such as Pokemon Turquoise version and Last Fire red are some of the best Pokémon ROM hacks available for free in 2021. 19. Augmented Reality: Connecting the Physical and Digital Worlds How does Augmented Reality connect the physical and digital worlds? Pokemon Go, a game that took the gaming industry by storm with more than a billion downloads, honored with the title of Best Mobile Game by Game Developers Choice Awards and the “Best App of the Year” by TechCrunch brought the concept of Augmented Reality into the limelight. And why not? 20. 10 Cutest Pink Pokémon of All Time The franchise has many adorable cute pink Pokémon in its roster. Such as Jigglypuff, Mew and Slowpoke. 21. Pokemon Legends Arceus Review: Is the New Open World Pokemon Game Worth it? Pokemon Legends: Arceus is the latest release and brings overhauls the Pokedex, battling and capturing, this review gives you all the info before you buy it. 22. All The Pokémon Games in Chronological Order This article has outlined the Pokémon games in Chronological order. The main series of games can be chronologically ordered, starting with Red and Green 23. What's New in Gaming: June 2021 Hackernoon presents the latest and interesting news, trends, and events emerging in the gaming world. Read the latest gaming industry stories on Hacker Noon, where 10k+ technologists publish stories for 4M+ monthly readers. 24. New Pokémon Snap: 5 Reasons Why it Might be the Best Game of 2021 New Pokémon Snap can be one of the best games of 2021due to its gimmicky nature and social media connectivity that may help it stand out from the crowd. 25. Dreepy in Pokémon Sword and Shield: How to Find, Catch, and Evolve You can find Dreepy in Pokémon Sword and Shield in the Lake of Outrage, dens and max raid battles. Extra care needs to be taken with capturing and evolving. 26. What is the Best Pokémon Fusion? In this slogging thread, the gaming community discovered a website where we could experience Pokémon fusions, and we discussed which one was the best. 27. Will Pokémon Legends: Arceus Live Up to the Hype? Pokémon Legends looks to be the open world makeover Pokémon fans have craved. However, mixed signals from recent trailers leave me more skeptical than hopeful. 28. Pokémon Legends: Arceus Revealed Alongside Diamond and Pearl Remakes The Pokémon Company has revealed Pokémon Legends: Arceus, a single-player open-world Pokémon RPG set to release worldwide in early 2022. 29. Is the Pokemon Hidden Fates Elite Trainer Box Worth Investment? The Hidden Fates elite trainer Box is an incredibly popular Pokemon TCG set and is well worth the investment. 30. What is Pokémon Z and Why Wasn’t it Released? Pokémon Z was very likely to have been in the works as the third instalment in generation six but was not released due to economic and, political constraints. 31. 10 Best Pokémon Games of All Time Ranked by Sales Pokémon Red and Blue is the best selling Pokémon game of all time, followed by  numerous other main series Pokémon titles 32. Pokemon Arceus is Out! What is Your Favorite Pokemon? To celebrate the release of Pokemon Legends Arceus, the team at Hackernoon discusses their favourite Pokemon and why! Spoilers it is definitely not Pikachu. 33. How to Find and Use the Pokémon Sword Destiny Knot You can find the Pokémon Sword Destiny Knot in a BP store,  Cramomatic. and through the  through the pickup ability. It can be used for breeding and infatuation 34. The Strongest Pokémon Champions Ranked Cynthia is the strongest of the Pokemon Champions, followed by Leon, Iris, Steven, Blue, Lance, Diantha, Alder, and Wallace ranked in terms of strength. 35. 10 Best Game Boy Color Games Ranked by Sales The Game Boy and the Game Boy Color had a great catalog of games, but they couldn't all be smash hits. Here are the best Game Boy Color games ranked by sales. 36. The Pokémon Mystery Dungeon Games Ranked by Sales Here are the Pokémon Mystery Dungeon games ranked by how much each one sold. 37. What was your favorite childhood video game? This Slogging thread by Mónica Freitas, Katarina Andrejević, Limarc Ambalina, Zaeem Shoaib, Blake Cram, Jack Boreham and Connor C occurred in slogging's official #gaming channel, and has been edited for readability. 38. 10 Best Nintendo DS Games of All Time Ranked by Sales Super Mario, Pokemon, and surprisingly, Brain Age are some of the best Nintendo DS game franchises, according to their overall sales. 39. 5 Best Pokémon Fan Games You Can Play for Free in 2021 The best Pokémon fan games available for free in 2021 are Pokémon Showdown, Insurgence, Planet, Uranium, and Vortex. 40. First Impressions of Pokémon Legends: Arceus This Slogging thread by Limarc Ambalina, Jack Boreham, SuperSaiyanProgramming, Blake Cram, Adrian Morales and Sara Pinto occurred in slogging's official #gaming channel, and has been edited for readability. 41. How to Build a Pokédex App with React and a Slash GraphQL Backend In this article, we're going to walk through some of the basic setup for Slash GraphQL and then take a look at how I built a Pokémon Pokédex app with React and Slash GraphQL in just a few hours! 42. Top 10 Most Powerful Dinosaur Pokémon Many Pokémon designs have taken inspiration from dinosaurs. Here are the 10 most powerful dinosaur Pokémon across the entire franchise. 43. 5 Best Pokémon GO Hacks and How to Get Them Due to the popularity of Pokémon GO, many users have tried to find ways to hack it. Common Pokemon Go hacks include spoofing and botting, amongst others. 44. Top 10 Strongest Dog Pokemon The 10 strongest dog Pokémon are Boltund, Stoutland, Smeargle, Houndoom, Arcanine, Grandbull, Jolteon and the legendry dog trio. 45. What are The Best Video Game Movie Adaptations? In this slogging thread, the gaming community discusses the best and worst video games movie adaptations, from the Tomb Raider to Detective Pikachu. 46. Snorlax Gets Two Los Angeles Police Officers Fired In this slogging thread, our community shares the time they've dodged a task or appointment so they could play Pokemon Go. Thank you for checking out the 46 most read stories about Pokemon on HackerNoon. to find the most read stories about any technology. Visit the /Learn Repo

46 Stories To Learn About Pokemon

In 1994 Wired magazine ran a short story entitled . This was back when Wired was actually cutting edge and not the it became after Conde Naste acquired it. In it our antihero “Stark” finds himself inexplicably recruited as a kind of data scout, looking for viable consumer trends emerging from the fully immersive, all encompassing data field known as “The Spew”. “Hack the spew” insufferable Silicon Valley stroke job “When a schmo buys something on the I-way it goes into his Profile, and if it happens to be something that he recently saw advertised there, we call that interesting, and when he uses the I-way to phone his friends and family, we Profile Auditors can navigate his social web out to a gazillion fractal iterations, the friends of his friends of his friends of his friends, what they buy and what they watch and if there’s a correlation.” The Spew of course, was the near future analogy of where the internet was headed, and when I went looking to link to it for this post, the piece turned out to be written by none other than Neal Stephenson. That means I read “Hack The Spew” and it made an impression on me before I even knew who Stephenson was or perhaps was on his way to becoming. Few would argue that Stephenson has a gift for seeing the general ambience of our oncoming future. uncannily anticipated the impetus toward crypto-currencies; the current systemic dysfunction of national sovereignty worldwide was foretold in so it follows that all this will likely culminate in something that resembles . Cryptonomicon Snow Crash; The Diamond Age Today, “The Spew” is not equivalent to the Internet itself, but it is more accurately analogous to say the social media platforms like Facebook, Twitter, especially when combined with the twin monopolies of Google and Amazon, collectively are: The Spew. It is like a global garbage pile of digital flotsam and jetsam, over which peasants scurry around and scour, looking for some morsel here, a crumb there, which can be monetized. If a trend or a trait is detected, even better. Those can be aggregated, syndicated, federated, even rehypothecated and at scale that can yield staggering financial payoffs and perhaps, even steer the course the history. At least that’s the narrative since the Cambridge Analytica scandal blew up in Facebook’s …face. After a long string of successive privacy fails (a.k.a a pattern of abuse?) this time feels different, as if the chickens are finally coming home to roost for Facebook. Cambridge Analytica is not unique Ever heard of Kareem Serageldin? Probably not. To date, he is the only banker in connection with the 2008–2009 Global Financial Crisis for his role in issuing fraudulent mortgage-backed securities (at least ). To be sure, he was a fall guy, a token sacrifice to demonstrate contrition for what was a systemic, institutionalized effort to inflate a bubble whose implosion nearly crashed the entire global financial system. to have been sent to prison outside of Iceland In this case while Facebook attempted to throw water on this crisis by ceremonially banishing Cambridge Analytica from its system, the longstanding pattern of abuse remains, and is perhaps now, finally, awareness of that is reaching critical mass with the public: Facebook for years (iPhone’s are also vulnerable to privacy intrusions, see below). scraped your call data from Android phones Facebook enables features such as “racial profiling” to advertisers Election rigging? Facebook to micro target voters in 2016 election (the Liberals turned them down, Labour took them up) approached major Australian political parties And while there were , (not to mention more informed consent) the 2012 Obama re-election campaign used the same data mining features and accessed the same data as the Cambridge Analytica app key differences in the way data was used In fact it may be veritably baked into their ecosystem to such a degree that it is almost to develop and create an app on Facebook impossible that harvest your data doesn’t Mark Zuckerberg has issued on CNN, and Facebook will take out full page ads in newspapers to apologize to the public. Yet, by now, “Groveling Zuckerberg apologies” are just part of the Facebook playbook, back in 2011, after Facebook had over still more privacy violations: yet another “Mea Culpa” as Liz Gannes observed just settled with the US Federal Trade Commission “At this point, Facebook CEO Mark Zuckerberg’s pattern on privacy is clear. Launch new stuff that pushes the boundaries of what people consider comfortable. Apologize and assure users that they control their information, but rarely pull back entirely, and usually reintroduce similar features at a later date when people seem more ready for it.” It becomes clear, as Futurist (and easyDNS member) Jesse Hirsh made this point on over the weekend: “Facebook ships with all privacy enhanced settings disabled” — further, my personal findings are that they use obfuscation to make it harder to disable data sharing settings. You have to jump through hoops to do it. Steve Pakin’s “The Agenda” Should you #deleteFacebook? WhatsApp founder Brian Acton, who became a when Facebook bought his company hasn’t let that dissuade him from telling the world what he thinks of all this: billionaire Should you? Should easyDNS? Here’s my take on it: If you are a business: keep your page but don’t be reliant on it There is a difference between a business who uses Facebook as an antennae to provide additional ways to stay in touch with customers and those whose business model is completely dependent on Facebook. We started our Facebook page when we were pulled into the as a way to stay in touch with our customers while that entire fiasco played out. We maintain it today for the same reason, and people do frequently contact us through that page looking for support. Wikileaks Crisis But some businesses are completely reliant on Facebook to survive. I subscribe to James Schramko’s . A t on it, a site I frequented myself in my early days of being a dog owner (our family Husky). Superfast Business Podcast recent episode had the founder of Dogtington Pos You have to credit the guy with dominating his niche but I couldn’t help wondering what would happen to his business if something substantial changed at Facebook, or if some of his readers would feel “used” if they understood some of the myriad tactics some of these sites routinely use, via Facebook, to drive their own affiliate revenues. It brings to mind 2 things: My late friend and one of the original easyDNS customers who was among the first to observe Atul Chitnis “if you’re not paying for the product, you are the product” My own maxim, which I introduced in the that there are two kinds of companies, those that feed on customer ignorance compared to those who prosper via customer savvy . I think it is obvious to all, at least now, that Facebook customer ignorance to survive. Guerrilla Capitalism Overview needs (Or as Zuck eloquently observed it back in his dormroom days) YMMV on your personal pages I read a long time ago “don’t put anything on the internet that you wouldn’t want to read in the newspapers the next day”, and that has served me well as a guide over the years. My basic assumption is that I post to Facebook, including “private” messages are wide open, being harvested, data mined, aggregated, used to target and retarget ads to me, build a profile and otherwise compile a comprehensive dossier, even stuff I’ve “deleted”. (If you’ve ever watched you’ll know that Facebook actually keeps the stuff you “delete”). everything “Terms and Conditions May Apply” So I never say anything on Facebook or put anything on there that is remotely confidential or proprietary. It’s strictly a water cooler. I like it because it enabled me to reconnect with various groups of my friends and peers over the years, from the kids I grew up and went to high school with in Galt, Ontario to the misfits from the London underground music scene in college, to the tech entrepreneurs from the mid-90’s on. Would I use it to send anything to anybody that I found myself hoping that it’s never going to leak or be used against me? Uh, no. That would be terribly naive. So to that end, I’ll probably keep my personal Facebook page, even though I sometimes catch myself spending too much time arguing stupid pointless crap (like politics) with people I’d otherwise never associate with. But that’s a self-discipline issue, not a data soveriengty issue (although it is e that Facebook codes the platform itself to be as as possible) now also common knowledg deliberately addictive All that said… At least #deleteFacebook from your mobile devices Facebook harvests your contact lists from your mobile devices (don’t believe me, )There are people in that list that I do not know. There are phone numbers from people who work for my competitors in there. My daughter’s (age 11) cell phone number is in there. go here You can “delete” all this : (but as you know Facebook never actually deletes anything). here Then when you go to “delete” all your contacts you get a message “We won’t be able to tell you when your friends start using Messenger if you delete all your uploaded contact info.” They say that like it’s a bad thing. But there is also this curious sentence: “If you have Continuous Uploading turned on in the Messenger app, your contact info will be uploaded again the next time the app syncs with Facebook servers.” I had deleted the Facebook mobile app from my phone a long time ago. I kept messenger installed because sometimes customers would contact easyDNS or Zoneedit via our Facebook pages for support. But Writing this I wanted to turn off “continuous uploading” in the app. Despite explaining how to do it, while this from 2016 did. this Facebook help article not third party article It turned out I had already disabled continuous uploading but I was surprised to find that the messenger app had defaulted permission to access my phone’s microphone. After this exercise I simply deleted the Messenger app from my phone as well. Personal Data Sovereignty is an idea whose time has come I think it would be safe to assume, that barring some widespread public pushback (such as the one happening right now), this is The New Normal. People who may have been complacently oblivious to the fact that their social network was pimping them as mere data points are realizing that they don’t like it as they have their faces rubbed in one data breach and privacy violation after another. Given the outrages of Equifax, Facebook et al, we may have arrived at the crossroads and we may only get this choice once. Do we push back and say “NO”, I own my own data, I control who gets it and what happens with it. ? Or, do we calm down after a few days, or weeks and then it’s business as usual. Next year Zuck will apologize for some other new breach of trust ahead of his 2020 presidential bid, while us “shmoes” go ahead and vote for him.

Should You Delete Your Facebook Page?

Intro We continue our adventure trying to solve the Diamond Kata while using Property-Based testing. , we added our first test, Non-empty, and discovered how to use input generators. Now let's figure out the next test. Last time First and last line content In the diamond Kata, the first and last line of every diamond always contains A. Such regularity is perfect for a property. Even the particular case with input A, where the first line is also the last one, respects that property. e.g. input: A

A input: E

----A----
---B-B---
--C---C--
-D-----D-
E-------E
-D-----D-
--C---C--
---B-B---
----A---- C# Tests [ ] { (LetterGenerator) })] { Diamond.Generate(c).First().Contains( ).ToProperty();
}

[ ] { (LetterGenerator) })] { Diamond.Generate(c).Last().Contains( ).ToProperty();
} Property(Arbitrary = new[ typeof Property ( ) public FirstLineContainsA c char return 'A' Property(Arbitrary = new[ typeof Property ( ) public LastLineContainsA c char return 'A' Here we used some built-in methods of the .NET library, which makes these tests simple to read and short to write. It almost reads like a sentence. Diamond.Generate(c) Generates the diamondFirst() / Last() Takes the first/last line of the generated diamondContains('A') Checks if the line contains the letter A and returns a boolToProperty() Transforms a boolean expression to a property If you are wondering what's [Property(Arbitrary = new[] { typeof(LetterGenerator) })] it's probably because you missed my previous post Wrapping up We are making some good progress towards a fully functioning test suite. However, there are still some uncovered areas that we'll address with more tests . next time Previously published at https://blog.miguelbernard.com/first-and-last-line-content/

Property-Based Testing: The Diamond Kata, First and Last Line Content

Intro Now that we have all the , we are finally ready to write our first Property-Based test. tools installed FsCheck Creating a property-based test is as simple as tagging a method with the [Property] attribute, similarly as you would do in xUnit with the [Fact] or [Theory] attributes. If you dig a little, you will realize that there's a lot of configurable options on the [Property] attribute. You can control how many random tests will be run each time, timeouts, etc. One of them is essential; the Arbitrary property. That property will define which method to use to generate random inputs. In our specific case, we are not interested in all the possible values of char. We only care about the 26 letters of the alphabet. To scope the input, we'll need to configure a generator that will do just that. Generators Generators are relatively simple. Create a static class Add a static method that returns Arbitrary<TypeYouWantToGenerateValueFor> Voilà You can write your randomization logic, but it's usually better to start from the built-in methods as they are already well balanced. { =>
            Arb.Default.Char().Filter(c => c >= && c <= );
} public static class LetterGenerator Arbitrary< > ( ) public static char Generate 'A' 'Z' Not Empty Test It may seem basic, but it's quite essential. We want to make sure we always have a non-empty result. [ ] { (LetterGenerator) })] { Diamond.Generate(c).All(s => s != .Empty).ToProperty();
} Property(Arbitrary = new[ typeof Property ( ) public NotEmpty c char return string One thing I forgot to mention earlier, the test method also needs to return a property object. Fortunately for us, the library contains an extension method that can transform any boolean expression into a property object by calling ToProperty(). So our test reads like this: Call the method with the provided input char c. Diamond.Generate() Make sure all the lines of the returned diamond are not empty. Use the ToProperty() method to wrap it into a property object. Stay tuned Stay tuned for my on this about solving the diamond kata with property-based testing. The will try to define properties for the first and last lines of our diamond. next posts series following post Previously published at https://blog.miguelbernard.com/input-generators-in-property-based-tests-with-fscheck/

Testing in C#: Property-Based Testing With Input Generators

E=MC² for Diamonds: Creating universal access to the diamond industry with open-sourced algorithms…

In the I’ve covered the basic ideas behind property-based testing. Here, I’m going to TDD the diamond kata using that technique. previous post The post is heavily inspired (i.e. blatantly copied). So be sure to go say hi to Nat Pryce and Mark Seemann doing the same exercise[1][2] (links at the bottom in the references). Luckily I’m going to use JavaScript and . That way I can hide myself behind the “but I’m using a different stack” excuse. JSVerify Also, I’m gonna keep code snippets to a minimum. Should you be interested into more details, feel free to check the . repo The diamond kata As well , the problem statement is as follows: described by Seb Rose Given a letter, print a diamond starting with ‘A’ with the supplied letter at the widest point. A few examples are Input: AOutput: AInput: BOutput:   A         B B          AInput: COutput:   A         B B        C   C         B B          A Ready, set, rock and roll In the commit I want to check the wirings. That’s why I use a generator that always returns to check the property. init 5 isFive // index.test.js const jsc = require('jsverify')const mocha = require('mocha')const isFive = require('./index') describe('TODO', () => {jsc.property('TODO', jsc.constant(5), isFive)}) // index.js const isFive = number => number === 5module.exports = isFive which of course is green $ mocha index.test.js TODO✓ TODO 1 passing (12ms) ✨  Done in 0.52s. The generator Everything works, thus I can create the generator for the diamond kata. In particular, I need to generate characters in the range. A..Z Since I’m not sure what to use, I decide to check what the generator returns jsc.asciichar const debug = x => {console.log(x)return true} describe('diamond', () => {jsc.property('TODO', jsc.asciichar, debug)}) Notice the . That way the “property” never fails and I can check all the generated asciichar. Since by default JSVerify checks the property 100 times by generating 100 inputs out of the generator, I see return true debug $ mocha index.test.js diamondTK.E B<// ... up to 100 asciichars ✓ TODO 1 passing (16ms) ✨  Done in 0.52s. Not quite right, in fact, I need to generate characters in the range only. Unfortunately, JSVerify doesn’t provide any generators out of the box that satisfy that constraint. Therefore, I create a custom one A..Z const alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'.split('')const char = jsc.suchthat(jsc.asciichar, c => alphabet.includes(c)) describe('diamond', () => {jsc.property('TODO', char, debug)}) This time we get the proper values $ mocha index.test.js diamondBLXBQVXBJSCPI// ... up to 100 chars in A..Z ✓ TODO 1 passing (19ms) ✨  Done in 0.52s. Notice that I could have moved the check inside the property const property = c => {if (!alphabet.includes(c)) return true// ... test the property} describe('diamond', () => {jsc.property('TODO', jsc.asciichar, property)}) but I would have made a mistake. In fact, in this case, JSVerify would call 100 times with random s. Therefore, only a subset of the generated input would get past the . In other words, I would lose test coverage. property jsc.asciichar if Property: diamond is not empty The property that kicks off the exercise just checks the diamond has length different than 0 for any char. jsc.property('is not empty', char, c => make(c).length !== 0) Which I make green with const make = char => 'whatever' From the REPL make(c) // for any c// => 'whatever' Property: first row contains A jsc.property('first row contains A',char,c => firstRow(make(c)).trim() === 'A') Which I make green with const make = char => '        A       ' // padding is asymmetric From the REPL make(c) // for any c// => '        A       ' Property: last row contains A jsc.property('last row contains A',char,c => lastRow(make(c)).trim() === 'A') Which is already green. Property: first row has symmetrical contour const firstRowHasSymmetricalContour = diamond => {const leadingElements = leading('A', firstRow(diamond)).lengthconst trailingElements = trailing('A', firstRow(diamond)).lengthreturn leadingElements === trailingElements} jsc.property(‘first row has symmetrical contour’,char,c => firstRowHasSymmetricalContour(make(c))) Which I make green with const make = char => '       A       ' // padding is symmetric From the REPL make(c) // for any c// => '       A       ' Property: rows have symmetrical contour Well, not only the first row has a symmetrical contour. Let’s modify the property so that all of the rows are checked const rowsHaveSymmetricalContour = diamond =>diamond.split('\n').map(rowHasSymmetricalContour).reduce((acc, x) => acc && x) // [].every would be better here jsc.property('rows have symmetrical contour',char,c => rowsHaveSymmetricalContour(make(c))) Which is already green. Property: rows contains the correct letters const rowsContainsCorrectLetters = (char, diamond) => {const pre = alphabetUntilBefore(char)const post = pre.slice().reverse()const expected = pre.concat([char]).concat(post)const actual = diamond.split('\n').map(row => row.trim())return expected.join() === actual.join()} jsc.property(‘rows contains the correct letters’,char,c => rowsContainsCorrectLetters(c, make(c))) Which I make green with const make = char => {const pre = alphabetUntilBefore(char)const post = pre.slice().reverse()const chars = pre.concat([char]).concat(post)return chars.join('\n')} The duplication between test and production code is a bad smell. But I decide to leave it there. From the REPL make('C')// => 'A\nB\nC\nB\nA' Property: rows are as wide as high const rowsAreAsWideAsHigh = diamond => {const height = rows(diamond).lengthreturn all(rows(diamond).map(hasLength(height)))} jsc.property('rows are as wide as high',char,c => rowsAreAsWideAsHigh(make(c))) which I make green with const makeRow = width => char => {if (char === 'A') {const padding = ' '.repeat(width / 2)return `${padding}A${padding}`} else {return char.repeat(width)}} const make = char => {const pre = alphabetUntilBefore(char)const post = pre.slice().reverse()const chars = pre.concat([char]).concat(post)return chars.map(makeRow(chars.length)).join('\n')} and from the REPL make('C')// => '  A  \nBBBBB\nCCCCC\nBBBBB\n  A  ' Property: rows except top and bottom have two identical letters jsc.property('rows except top and bottom have two identical letters',char,c => internalRowsHaveTwoIdenticalLetters(make(c))) which I make green with const makeRow = width => char => {if (char === 'A') {const padding = ' '.repeat(width / 2)return `${padding}A${padding}`} else {const padding = ' '.repeat(width - 2)return `${char}${padding}${char}`}} const make = char => {const pre = alphabetUntilBefore(char)const post = pre.slice().reverse()const chars = pre.concat([char]).concat(post)return chars.map(makeRow(chars.length)).join('\n')} and from the REPL make('C')// => '  A  \nB   B\nC   C\nB   B\n  A  ' Property: rows have the correct amount of internal spaces jsc.property('rows have the correct amount of internal spaces',char,c => rowsHaveCorrectAmountOfInternalSpaces(make(c))) which I make green with const internalPaddingFor = char => {const index = alphabet.indexOf(char)return Math.max((index * 2) - 1, 0)} const makeRow = width => char => {if (char === 'A') {const padding = ' '.repeat(width / 2)return `${padding}A${padding}`} else {const internalSpaces = internalPaddingFor(char)const internalPadding = ' '.repeat(internalSpaces)const externalSpaces = width - 2 - internalSpacesconst externalPadding = ' '.repeat(externalSpaces / 2)return `${externalPadding}${char}${internalPadding}${char}${externalPadding}`}} const make = char => {const pre = alphabetUntilBefore(char)const post = pre.slice().reverse()const chars = pre.concat([char]).concat(post)return chars.map(makeRow(chars.length)).join('\n')} and from the REPL make('C')'  A  \n B B \nC   C\n B B \n  A  ' Unfortunately, in the test uses the following rowsHaveCorrectAmountOfInternalSpaces const index = alphabet.indexOf(char)return Math.max((index * 2) - 1, 0) I don’t like this duplication. Therefore, I decide to test the external space (and not the internal one). Property: rows have the correct amount of external spaces jsc.property('rows have the correct amount of external spaces',char,c => rowsHaveCorrectAmountOfExternalSpaces(make(c))) This time internally uses a different calculation: rowsHaveCorrectAmountOfExternalSpaces const index = alphabet.indexOf(char)return ((width - 1) / 2 - index) * 2 which means I’ve removed the duplication. Plus, the tests are already green since the production code for the internal spaces takes care of the external too. And.. We are done As shown above, the last REPL test gave us make('C')// => '  A  \n B B \nC   C\n B B \n  A  ' which means AB BC   CB BA And these are all the properties I have discovered: is not empty first row contains A last row contains A rows have symmetrical contour rows contain the correct letters rows are as wide as high rows except top and bottom have two identical letters rows have the correct amount of external spaces Outro The first thing I’ve noticed is how hard property-based TDD makes you think. In fact, it’s really easy to come up with examples for this kata. But the same cannot be said for invariants. At the same time, knowing what properties your problem space has, means having a deep understanding of it. And with property-based TDD, it’s necessary to discover them before writing the actual production code. Not only that, I found myself writing a property that conflicted with previous ones. In fact, the code that made it green, also turned red some of the existing. The diamond kata is a simple exercise but this happens frequently in the specs we are given on everyday work. Also, I’ve built my way up from generic properties first and then specialised (i.e. to ). Which is the opposite of what happens in example-based TDD: from specific to generic[3]. diamond is not empty rows have the correct amount of external spaces Unfortunately, I cannot compare much with example-based TDD since I haven’t tried the kata that way. Should you be interested into that, please check out the references. References by Mark Seemann Diamond kata with FsCheck by Nat Pryce Diamond Kata — TDD with only Property-Based Tests by Nat Pryce Diamond Kata — Thoughts on Incremental Development More Pointers by Nat Pryce Property Based TDD at SPA 2013 If you liked the post and want to help spread the word, please consider , clapping or sharing this. But only if you really liked it. Otherwise, please feel free to comment or tweet me with any suggestions or feedback. tweeting

Diamond kata via property-based TDD in JavaScript

07/21/2016 Latest Update: Previous post in this series _Latest Update: 01/26/2016_medium.com Writing a Blog Engine in Phoenix and Elixir: Part 4, Adding Roles to our Controllers Introduction As we have been writing our code for our blog engine along the way, you may have noticed that we’re using very few libraries in our codebase. This is two-fold: first, we want The first one I’ll be starting with is , a factory library in the same vein as Factory Girl for Ruby. ExMachina Current Versions As of the time of writing this, the current versions of our applications are: : v1.3.1 Elixir v1.2.0 Phoenix: v2.0.2 Ecto: : v1.0.2 ExMachina If you are reading this and these are not the latest, let me know and I’ll update this tutorial accordingly. What is it? As mentioned before, ExMachina is designed to be a similar Factory-style implementation to from Ruby (also from the fine folks at Thoughtbot). The premise here is that for your tests, it’s nice to have a way to set up various models and their associations for your tests without having to rewrite the creation logic for them over and over. This is something you can accomplish with writing helper modules that provide simple creation functions, but you end up having to create functions and helpers for each variation, each extra association, etc, which can get a bit repetitive. Factory Girl Getting Started We’ll begin by opening up and introducing to our dependency and application lists. mix.exs ExMachina Adding ExMachina to our dependency list is pretty simple, so we’ll just add an entry for ExMachina after comeonin. defp deps do[{:phoenix, "~> 1.2.0"},{:phoenix_pubsub, "~> 1.0"},{:phoenix_ecto, "~> 3.0"},{:postgrex, ">= 0.0.0"},{:phoenix_html, "~> 2.6"},{:phoenix_live_reload, "~> 1.0", only: :dev},{:gettext, "~> 0.11"},{:cowboy, "~> 1.0"},{:comeonin, "~> 2.5.2"},{:ex_machina, "~> 1.0"}]end Next, we’ll add to the list of applications in-use by our application: :ex_machina def application do[mod: {Pxblog, []},applications: [:phoenix, :phoenix_pubsub, :phoenix_html, :cowboy, :logger, :gettext,:phoenix_ecto, :postgrex, :comeonin, :ex_machina]]end Run the following command to make sure that everything is ready to go and set up correctly: $ mix do deps.get, compile If all went well, you should see some output about fetching ExMachina and finally everything compiling successfully! You should also run and verify everything is green before you start making modifications just to stay extra safe here. mix test Adding our first factory: Roles What we need to do is create a factory module and make it accessible to all of our tests. My favorite way to do this without bloating each test too much is to throw the module file containing the factories into and then specifically import it into tests we need. test/support So, let’s start by creating : test/support/factory.ex defmodule Pxblog.Factory douse ExMachina.Ecto, repo: Pxblog.Repo alias Pxblog.Rolealias Pxblog.Useralias Pxblog.Post def role_factory do%Role{name: sequence(:name, &"Test Role #{&1}"),admin: false}endend We’re calling it since that’s essentially what this module is going to do. We then write factory functions that pattern match on an atom for which type of factory to build/create from. Since this is pretty close to Factory Girl, it carries some naming conventions from it that are pretty important to note. The first being : build means that we are building out the model (not a changeset) but not persisting it to the database. , however, DOES persist the model to the database. Factory build insert We need the bit to tell ExMachina that we’re using Ecto as our Repo layer and that it should act accordingly for create/associations/etc. We also need to add aliases for all of our models since we’ll be writing factories for all of them. use ExMachina.Ecto The function should just return a struct that defines the default properties we want it to have. This function only supports an arity of 1. role_factory Role The sequence bit here is pretty interesting. We want to generate a unique name for each role, so for us to be able to do so we define a sequentially-generated name. We use the function, and we pass it two arguments: the first is the name of the field we want to generate a sequence for, and the second is an anonymous function that returns a string and interpolates a value into it. Let’s take a look at this function: sequence &”Test Role #{&1}” If you’re comfortable with Elixir, you probably recognize this as another way to write an anonymous functions. This roughly translates to: fn x ->"Test Role #{x}"end So if we think about what that sequence function is doing, it’s really just doing this: sequence(:name, fn x ->"Test Role #{x}"end) Finally, we set our admin flag to false, since we’ll use these as a default case and only explicitly create admin roles. We’ll discuss some of the more complicated options for ExMachina later, as well. Now, we’ll spend some time integrating our new Role factory into our controller tests. Changing our controller tests to use our Role factory Open up first. At the top, in our block, we’ll modify the bits using our functions. test/controllers/user_controller_test.exs setup TestHelper.create_role # ... import Pxblog.Factory @valid_create_attrs %{email: "test@test.com", username: "test", password: "test", password_confirmation: "test"}@valid_attrs %{email: "test@test.com", username: "test"}@invalid_attrs %{} setup douser_role = insert(:role){:ok, nonadmin_user} = TestHelper.create_user(user_role, %{email: "nonadmin@test.com", username: "nonadmin", password: "test", password_confirmation: "test"}) admin_role = insert(:role, admin: true){:ok, admin_user}    = TestHelper.create_user(admin_role, %{email: "admin@test.com", username: "admin", password: "test", password_confirmation: "test"}) {:ok, conn: build_conn(), admin_role: admin_role, user_role: user_role, nonadmin_user: nonadmin_user, admin_user: admin_user}end # ... We have to start out by our Factory module that we created. Line 10 is just us using a simple role using the factory. Line 13 is us using the same factory, but us specifically overriding the admin flag to true. importing :role :role Save the file and rerun our tests, and we’re still green! Now, let’s implement our user factory and introduce a factory that builds associations too! Adding our next factory: Users Let’s take a look at the factory for users. def user_factory do%User{username: sequence(:username, &"User #{&1}"),email: "test@test.com",password: "test1234",password_confirmation: "test1234",password_digest: Comeonin.Bcrypt.hashpwsalt("test1234"),role: build(:role)}end For the most part, this factory matches what we created for roles. There are a couple of gotchas we’ll have to deal with first. On line 7 of the above, you can see that we have to set the password_digest value to the hashed password value (since we simulate logins for users, you’ll want to include this). We just call the Bcrypt module under Comeonin and specifically invoke the hashpwsalt function, passing it the same password that we use the in password/password_confirmation values. On line 8, we also have to specify that is actually an association; we use the function and pass in via an atom the name of the association we want to build for this. role build Having modified our user factory, let’s go back to test/controllers/user_controller_test.exs. setup douser_role     = insert(:role)nonadmin_user = insert(:user, role: user_role) admin_role = insert(:role, admin: true)admin_user = insert(:user, role: admin_role) {:ok, conn: build_conn(), admin_role: admin_role, user_role: user_role, nonadmin_user: nonadmin_user, admin_user: admin_user}end Now we’ve completely replaced all of our calls to TestHelper with calls to the Factory instead. We’re using the user role and passing that to our user factory so that it knows which role to use. We then do the same thing for the admin user, but other than that we don’t need to modify our tests at all! Run our tests, make sure everything is still green, and then we can proceed! Adding our next factory: Posts Now that we’ve gotten so good at adding new factories, adding our final factory for posts should be pretty simple. def post_factory do%Post{title: "Some Post",body: "And the body of some post",user: build(:user)}end Not really anything new here, so we’ll jump right into modifying : test/controllers/post_controller_test.exs # ... import Pxblog.Factory @valid_attrs %{body: "some content", title: "some content"}@invalid_attrs %{} setup dorole = insert(:role)user = insert(:user, role: role)post = insert(:post, user: user)conn = build_conn() |> login_user(user){:ok, conn: conn, user: user, role: role, post: post}end # ... Once again, we so our module knows where the factory calls are coming from. Then, we replace all of our creation steps in our setup block with Factory calls instead. gets populated from our statement creating our role, which then is used to build our user from the factory, and finally that user is used to create a post associated with that user…but that’s it! Run our tests again and it’s back to being green! import Pxblog.Factory role insert Beyond this point, everything else is just grunt-work; going back in and replacing calls to TestHelper with Factory calls instead. It’s nothing particularly new or exciting, so I won’t bother with the excruciating details for each. Other ways to include your factories I chose the route of explicitly importing my factory into each of my tests, but if you did not want to do this, you could instead do one of the following: Add our alias statement to the using blocks in test/support/model_case.ex: using doquote doalias Pxblog.Repo import Ecto  
import Ecto.Changeset  
import Ecto.Query  
import Pxblog.ModelCase  
import Pxblog.Factory endend And test/support/conn_case.ex: using doquote do# Import conveniences for testing with connectionsuse Phoenix.ConnTest alias Pxblog.Repo  
import Ecto  
import Ecto.Changeset  
import Ecto.Query  

import Pxblog.Router.Helpers  
import Pxblog.Factory  

# The default endpoint for testing  
@endpoint Pxblog.Endpoint endend Other functions you can perform with Ex Machina For purposes of the little blog engine we’re writing we didn’t have an explicit need for some of the other features that ExMachina provides out of the box. For example, both build and create support a few other functions for sake of convenience (I’m using build as the example, but these work with create too): build_pair(:factory, attrs)    <- Builds 2 modelsbuild_list(n, :factory, attrs) <- Builds N models You can also persist a model that you used a factory build method by calling create on it: build(:role) |> insert Other resources For more information on how to use ExMachina, visit the Github page for it ( ). You can also visit thoughtbot’s tech blog where the creators have a great write up announcing ExMachina and some other ways to use it! The post in question is at . https://github.com/thoughtbot/ex_machina https://robots.thoughtbot.com/announcing-ex-machina Wrapping up At first I was admittedly a little wary as I’ve seen some things that have been implemented with Factory Girl in the past and I was afraid to get right back into that same scenario, but Elixir does such a nicer job of protecting us from ourselves that I think it balances out quite nicely. The syntax is crisp and clean, the amount of code that I had to write dropped dramatically, and it unties our tests just a little bit more from Ecto, so overall I’m very pleased. A big thank you to the fine folks at Thoughtbot for giving us another very handy library to use. I’d also love to know what people thought of this article. I’ve been toying with the idea of publishing a series of posts on different libraries available for Elixir and Phoenix, and ExMachina seemed like a great way to start! You can usually find me on the Elixir Slack group or the Elixir IRC room, or of course you can find me on twitter at @diamondgfx. Next post in this series _Latest Update: 01/26/2016_medium.com Writing a Blog Engine in Phoenix and Elixir: Part 6, Markdown Support Check out my new book! Hey everyone! If you liked what you read here and want to learn more with me, check out my new book on Elixir and Phoenix web development: _Learn to build a high-performance functional prototype of a voting web application from scratch using Elixir and…_www.packtpub.com Phoenix Web Development | PACKT Books I’m really excited to finally be bringing this project to the world! It’s written in the same style as my other tutorials where we will be building the scaffold of a full project from start to finish, even covering some of the trickier topics like file uploads, Twitter/Google OAuth logins, and APIs! is how hackers start their afternoons. We’re a part of the family. We are now and happy to opportunities. Hacker Noon @AMI accepting submissions discuss advertising & sponsorship To learn more, , , or simply, read our about page like/message us on Facebook tweet/DM @HackerNoon. If you enjoyed this story, we recommend reading our and . Until next time, don’t take the realities of the world for granted! latest tech stories trending tech stories

Writing a Blog Engine in Phoenix and Elixir: Part 5, Adding ExMachina

: 08/02/2016 Latest Update Previous Post in this series _Latest Update: 08/02/2016_medium.com Writing a Blog Engine in Phoenix and Elixir: Part 6, Markdown Support Current Versions : v1.3.1 Elixir v1.2.0 Phoenix: v2.0.2 Ecto: Where We Left Off Our blogging application now supports using a nice little markdown editor to make our posts even prettier, so it’s really starting to look like a full-featured project! One thing we don’t have, though, is any way to receive any sort of feedback on any of the posts we write. The good news is this is a pretty simple thing to add and just builds on a lot of the work with associations that we’ve already built! We’re going to start very simple on this initial approach. We’re not going to worry about requiring users to register; instead we’re going to have new comments get added into a “pending” state. Comments are not displayed on the Post unless they’ve been approved out of that pending state unless the user visiting our blog checks a “Show Unapproved” button. Adding Our Comments Model Let’s start by adding a model for our comments. We’re expecting comments to have the following: An author (we’ll use string for this) A body (we’ll use text for this) An approved flag (we’ll use boolean for this, defaulting to false) The post the comment is for (we’ll use reference for this) We don’t want to create the full suite of templates and everything, so we’re going to stick to using for this. mix phoenix.gen.model mix phoenix.gen.model Comment comments author:string body:text approved:boolean post_id:references:posts And then we’ll migrate our DB: mix ecto.migrate Associating Comments With Posts If you open up you can see that Comments are now already associated with Posts, but we haven’t done anything to set that up in reverse. web/models/comment.ex In , add the following to your “posts” schema definition: web/models/post.ex has_many :comments, Pxblog.Comment And now just to make sure everything is working as we expect, run to verify that everything is still green (it should be at this point)! Now let’s modify our tests slightly so that we can test the association between a Post and a Comment. mix test First, open up and add a Comment factory. Add the following at the top with the rest of our alias statements: test/support/factory.ex alias Pxblog.Comment And add the following at the bottom of the project: def comment_factory do%Comment{author: "Test User",body: "This is a sample comment",approved: false,post: build(:post)}end Accordingly, we need to add some tests to take advantage of this new factory. Open up and add the following to the file: test/models/comment_test.exs import Pxblog.Factory # ... test "creates a comment associated with a post" docomment = insert(:comment)assert comment.post_idend Run our tests again and we should remain green! Adding Our Routes For Comments We’ll start by setting up our initial routes that we’ll be using for comments, which will help us create an initial technical design of sorts. Open up : web/router.ex resources "/posts", PostController, only: [] doresources "/comments", CommentController, only: [:create, :delete, :update]end Comments really only make sense in the context of posts, so we’re going to nest comments underneath posts. However, in the other routes, we’ve already defined the Posts resources nested under users! We don’t want to expose a bunch of post-only routes, so we use the code to lock out any root level post routes. Then we add the comments resources, but for right now, we’re only going to allow , , and . Create will be what anonymous users use to create comments (that are initially unapproved). Delete will be for the author of the post or admins to delete a post, and update will be used to allow an admin or author to update a comment to approved so it can be seen by the general public. only: [] :create :delete :update Adding Our Comments Controller and View Now that our models are set up, we need to build a controller with a couple of actions. Most of the showing/viewing comments is going to be via the Posts controller, but we’ll need to be able to delete/update/create comments from this controller in time. We’ll begin by creating : web/controllers/comment_controller.ex defmodule Pxblog.CommentController douse Pxblog.Web, :controllerend And we’ll create a view as well to keep Phoenix happy with us. Create : web/views/comment_view.ex defmodule Pxblog.CommentView douse Pxblog.Web, :viewend Now we’ll head back to the controller and start off with a very basic structure of our three actions, , , and . create update delete def create(conn, _), do: conndef update(conn, _), do: conndef delete(conn, _), do: conn Next, we’ll need a comment form template that we can use on the Show Post page. Create a new directory for us to work with: $ mkdir web/templates/comment Allowing Users To Post Comments We’ll start by creating : web/templates/comment/form.html.eex <%= form_for @changeset, @action, fn f -> %><%= if @changeset.action do %><div class="alert alert-danger"><p>Oops, something went wrong! Please check the errors below.</p></div><% end %> <div class="form-group"><%= label f, :author, class: "control-label" %><%= text_input f, :author, class: "form-control" %><%= error_tag f, :author %></div> <div class="form-group"><%= label f, :body, class: "control-label" %><%= textarea f, :body, class: "form-control", id: "body-editor" %><%= error_tag f, :body %></div> <div class="form-group"><%= submit "Submit", class: "btn btn-primary" %></div><% end %> Pretty standard form here, so not much we need to discuss. Now let’s head to the show post template , where we’ll add a reference to the comment form. Please note that in the template above, we define and , so we’ll need to cycle back to later. web/templates/post/show.html.eex @changeset @action web/controllers/post_controller.ex For right now, let’s stick with . After the list of attributes for the post, add the following line: web/templates/post/show.html.eex <%= render Pxblog.CommentView, "form.html", changeset: @comment_changeset, action: post_comment_path(@conn, :create, @post) %> We need to reference the “form.html” render inside of our View, so we specify that as the first argument to the “render” call. We need to pass it a (which we haven’t set yet, but will soon) and an action, which is where the comments should get posted to. CommentView @comment_changeset And now we’ll head to to make it all work. You’ll need to change the “show” function to resemble the following: web/controllers/post_controller.ex def show(conn, %{"id" => id}) dopost = Repo.get!(assoc(conn.assigns[:user], :posts), id)comment_changeset = post|> build_assoc(:comments)|> Pxblog.Comment.changeset()render(conn, "show.html", post: post, comment_changeset: comment_changeset)end Now let’s go back to our CommentController ( ) and flesh out the create function a little more. We’ll need some stuff at the top for a standard create function, so we’ll start by adding the following to the top (right before our functions): web/controllers/comment_controller.ex alias Pxblog.Commentalias Pxblog.Post plug :scrub_params, "comment" when action in [:create, :update] We’re including “update” in the scrub_params call because we’ll need that later anyways. Now, we’re going to hop down to the create function and replace it with the following: def create(conn, %{"comment" => comment_params, "post_id" => post_id}) dopost      = Repo.get!(Post, post_id) |> Repo.preload([:user, :comments])changeset = post|> build_assoc(:comments)|> Comment.changeset(comment_params) case Repo.insert(changeset) do{:ok, _comment} ->conn|> put_flash(:info, "Comment created successfully!")|> redirect(to: user_post_path(conn, :show, post.user, post)){:error, changeset} ->render(conn, Pxblog.PostView, "show.html", post: post, user: post.user, comment_changeset: changeset)endend We first only want to try to create a comment when we’ve been passed comment params and the post_id, since without both of those we cannot create a new comment. Next, we fetch the associated post (remember to preload both the user and comments, since our template will start referencing both!) and start creating a new associated changeset. We start off with the post and pipe that into , which builds an associated schema by specifying the association via an atom. In this case, we want to build an associated . We then pipe that into the Comment.changeset function with the comment_params we pattern matched. The rest of this is business as usual with one exception: build_assoc comment The error condition is a little complicated because again, we’re trying to use another View’s render. We first pass the connection, then the appropriate View to use ( in our case), the template we want to render, and then since that template uses , , and , we need to supply the three. Now you can test it out: if it posts with errors, you’ll get the error listing for the comment right on the page. If it posts without errors, you’ll get a blue flash message at the top! Great progress! Pxblog.PostView @post @user @comment_changeset Adding A Comments Display To Our Posts Next, we need to make it so we can actually see the posts on the template. We’re going to create a shared template that can be used if we ever want to display comments in other places for different things, so we’re going to create and fill it with the following: web/templates/comment/comment.html.eex <div class="comment"><div class="row"><div class="col-xs-4"><strong><%= @comment.author %></strong></div><div class="col-xs-4"><em><%= @comment.inserted_at %></em></div><div class="col-xs-4 text-right"><%= unless @comment.approved do %><button class="btn btn-xs btn-primary approve">Approve</button><% end %><button class="btn btn-xs btn-danger delete">Delete</button></div></div><div class="row"><div class="col-xs-12"><%= @comment.body %></div></div></div> There’s not much to explain here. The approve/delete buttons aren’t hooked up yet; we’ll tackle that in the next tutorial in this series. We also need to modify the controller to preload the comments and modify the show template on Posts to include the listing of comments. First, we’ll tackle the controller updates. In , in the function, we’ll add one line to the line that fetches the post (I’ve bolded the new line): web/controllers/post_controller.ex show post = Repo.get!(assoc(conn.assigns[:user], :posts), id) |> Repo.preload(:comments) This just ensures that our comments are loaded as part of our post. Finally, we’ll open up and add the section of our template that displays comments: web/templates/post/show.html.eex <div class="comments"><h2>Comments</h2><%= for comment <- @post.comments do %><%= render Pxblog.CommentView, "comment.html", comment: comment %><% end %></div> Adding Controller Tests for Comments We can’t leave yet, since we still have some conditions not well-covered by tests! We should cover the controller’s create function and we’ll stick to one positive case and one negative case, since those are the paths that our code will travel through. Create and let’s begin: test/controllers/comment_controller_test.exs defmodule Pxblog.CommentControllerTest douse Pxblog.ConnCase import Pxblog.Factory @valid_attrs %{author: "Some Person", body: "This is a sample comment"}@invalid_attrs %{} setup douser = insert(:user)post = insert(:post, user: user) {:ok, conn: build\_conn(), user: user, post: post} end test "creates resource and redirects when data is valid", %{conn: conn, post: post} doconn = post conn, post_comment_path(conn, :create, post), comment: @valid_attrsassert redirected_to(conn) == user_post_path(conn, :show, post.user, post)assert Repo.get_by(assoc(post, :comments), @valid_attrs)end test "does not create resource and renders errors when data is invalid", %{conn: conn, post: post} doconn = post conn, post_comment_path(conn, :create, post), comment: @invalid_attrsassert html_response(conn, 200) =~ "Oops, something went wrong"endend We’ll continue using Pxblog.Factory since it is so handy. We’ll also set up two module variables, and , same as we do pretty much everywhere else. We also create a setup block that’ll set up a default user and post for us to use to create comments with. @valid_attrs @invalid_attrs Next, we’ll create our positive test case. We post to the nested post->comment path with valid attributes, assert we get redirected as expected and that the comment was created for that post! Finally, we’ll do the same, but with invalid data, and verify that we get the “Oops, something went wrong” message that appears in the HTML when something fails validations! Done! Our current UI! Next Steps We have a great foundation for our comments, but we can definitely improve this more. For example, we still cannot approve or delete comments, and we also will fetch every single comment for a post. In the next few posts, we’ll work on refining those a little more before moving on to changing our comment system into a live comment system powered by Phoenix’s channels! Apparently I completely left off the section where we add the comments to the actual display of posts! I’ve updated this post to now properly reflect those changes :) Thanks ! Update 02/29/2016: Andrew Benz Next Post In This Series _Latest Update: 08/02/2016_medium.com Writing a Blog Engine in Phoenix and Elixir: Part 8, finishing comments Check out my new book! Hey everyone! If you liked what you read here and want to learn more with me, check out my new book on Elixir and Phoenix web development: _Learn to build a high-performance functional prototype of a voting web application from scratch using Elixir and…_www.packtpub.com Phoenix Web Development | PACKT Books I’m really excited to finally be bringing this project to the world! It’s written in the same style as my other tutorials where we will be building the scaffold of a full project from start to finish, even covering some of the trickier topics like file uploads, Twitter/Google OAuth logins, and APIs!

Writing a Blog Engine in Phoenix and Elixir: Part 7, Adding Comments Support

08/02/2016 Latest Update: Previous Post in this series Part 5: Adding ExMachina Current Versions As of the time of writing this, the current versions of our applications are: : v1.3.1 Elixir v1.2.0 Phoenix: v2.0.2 Ecto: : v1.0.2 ExMachina : 1.0.1 Earmark If you are reading this and these are not the latest, let me know and I’ll update this tutorial accordingly. Where We Left Off We’ve now added roles, users, and posts to our blogging platform, fixed up some bugs, upgraded some dependencies, and fixed our seeds. Our platform is really nice and stable and has a good set of base functionality. If you haven’t been following along or missed a step along the way, you can continue with the “11092015” branch of . https://github.com/Diamond/pxblog Implementing Markdown support Given that we’re tech people building a blog, one that we may or may not be using, we should probably allow people to write posts in something other than plaintext support. Markdown happens to be a language that works great for blogging and is really simple to support in Elixir, so let’s implement Markdown support using a third party library called . We start off simply by adding a dependency to our application in the function in Earmark deps mix.exs: {:earmark, "~> 1.0.1"} And then we’ll run to make sure we added it successfully to our application. If all goes well, we can move right on to adding support into our templates and views. mix do deps.get, compile Updating our views We’ll start by providing a convenient method to convert a post into Markdown. We don’t want to have to write all over the place, and if we ever decide to support any of Earmark’s other features and options, we’d have to rewrite that code over and over. Instead, we’ll implement a function in that will give us a single place to modify if we ever want to change that. Open that file up and add the following function: Earmark.to_html(data) web/views/post_view.ex def markdown(body) dobody|> Earmark.to_html|> rawend We have the input text, body, that we’re piping into Earmark’s “to_html” function. Since we’re expecting html out that we can place into our post, so we’ll use here. I know what you’re thinking: “yikes, isn’t raw terribly unsafe?” The answer is yes, it absolutely is. Trouble is, we need to output in raw html from Earmark, so we need to get this data rendered. We also don’t want to end up having to strip the same tags every single time we render this out, so let’s go into and add some code that will strip it out: raw web/models/post.ex def changeset(struct, params \\ %{}) dostruct|> cast(params, [:title, :body])|> validate_required([:title, :body])|> strip_unsafe_body(params)end defp strip_unsafe_body(model, %{"body" => nil}) domodelend defp strip_unsafe_body(model, %{"body" => body}) do{:safe, clean_body} = Phoenix.HTML.html_escape(body)model |> put_change(:body, clean_body)end defp strip_unsafe_body(model, _) domodelend We added a decent amount of code here, so let’s discuss what we’re doing. The first change we made is at the top, in our changeset function. We added a new call, . This will pattern match into one of three possible functions. The first includes a body parameter that is nil; the second is the method that includes a body parameter which we have to strip it out, and the third is a final catch-all. strip_unsafe_body(model, …) We use the function to replace the body change with a stripped version, which calls out to Phoenix.HTML’s “html_escape” function. This function takes in text, and then returns out a tuple of on success. put_change {:safe, cleaned_up_body} Writing this code with no tests makes me queasy, especially with what we’re doing here, so let’s test it! Writing tests for our code stripper The first thing we’re going to need to do, since we’re depending on these model actions to keep our code safe, is make sure they’re tested appropriately! defmodule Pxblog.PostTest douse Pxblog.ModelCase alias Pxblog.Post @valid_attrs %{body: "some content", title: "some content"}@invalid_attrs %{} test "changeset with valid attributes" dochangeset = Post.changeset(%Post{}, @valid_attrs)assert changeset.valid?end test "changeset with invalid attributes" dochangeset = Post.changeset(%Post{}, @invalid_attrs)refute changeset.valid?end test "when the body includes a script tag" dochangeset = Post.changeset(%Post{}, %{@valid_attrs | body: "Hello <script type='javascript'>alert('foo');</script>"})refute String.match? get_change(changeset, :body), ~r{<script>}end test "when the body includes an iframe tag" dochangeset = Post.changeset(%Post{}, %{@valid_attrs | body: "Hello <iframe src='http://google.com'></iframe>"})refute String.match? get_change(changeset, :body), ~r{<iframe>}end test "body includes no stripped tags" dochangeset = Post.changeset(%Post{}, @valid_attrs)assert get_change(changeset, :body) == @valid_attrs[:body]endend The first thing we have to modify is our declaration at the top. When we receive data from the controller it’s going to be in the form of string-based keys, not atoms, and it will cause our tests to fail unless we modify that. @valid_attrs Next, we import in , but only the function, which we need to pull the translated value out of the changeset. Finally, we write four tests: Ecto.Changeset get_change/2 When our body has a script tag in it When our body has an iframe tag in it When our body has none of the invalid tags in it Re-run our test suite and we should be green. We have one more test to write and then some a few basic UI changes and then we are complete! Writing our tests for the Markdown helper We should also write a quick test for our markdown helper function that we wrote in our Post View module. The good news is this should be a very simple test to write. Create and fill it with the following: test/view/post_view_test.exs defmodule Pxblog.PostViewTest douse Pxblog.ConnCase, async: true test "converts markdown to html" do{:safe, result} = Pxblog.PostView.markdown("**bold me**")assert String.contains? result, "<strong>bold me</strong>"end test "leaves text with no markdown alone" do{:safe, result} = Pxblog.PostView.markdown("leave me alone")assert String.contains? result, "leave me alone"endend Run our tests, verify that all is green, and we’re done with updating our tests for this new functionality! Updating our UI Right now, we have the ability to write up full posts but the UI doesn’t really support us editing anything larger than a single line. We’ll modify the standard form to include a text area instead of a textbox and we’ll also give it a shiny, better editor. Open up and add an parameter and give it an id of “body-editor”. The finished line should look like this: web/templates/post/form.html.eex id <%= textarea f, :body, class: "form-control", id: "body-editor" %> Finally, add the following code to the bottom of your form’s template ( ): web/templates/post/form.html.eex <link rel="stylesheet" href="//cdn.jsdelivr.net/simplemde/latest/simplemde.min.css"><script src="//cdn.jsdelivr.net/simplemde/latest/simplemde.min.js"></script><script>var simplemde = new SimpleMDE();</script> Reload our UI and we should see a very clean interface for writing new posts! This is starting to look like a proper blogging platform and everything! Finally, open up and change the line that displays the post’s body and change it to use the markdown(body) function we defined in the view. web/templates/post/show.html.eex <%= markdown(@post.body) %> Conclusion We now have a better means of editing/formatting our posts and the editor looks much, much nicer! We’ll probably also want to fix up the layout at some point, and there still isn’t any way to add comments, but commenting actually would be a fun way to implement support for channels, so we’ll hold off for now until we’re ready to build that support in! If you want to see the completed version of this code, just grab the “add_markdown_support” branch of our repo. Next Post In This Series Writing A Blog Engine In Phoenix And Elixir: Part 7, Adding Comments Support Check out my new book! Hey everyone! If you liked what you read here and want to learn more with me, check out my new book on Elixir and Phoenix web development: _Learn to build a high-performance functional prototype of a voting web application from scratch using Elixir and…_www.packtpub.com Phoenix Web Development | PACKT Books I’m really excited to finally be bringing this project to the world! It’s written in the same style as my other tutorials where we will be building the scaffold of a full project from start to finish, even covering some of the trickier topics like file uploads, Twitter/Google OAuth logins, and APIs!

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