HumanTalks 3 Years

For the third year anniversary of the HumanTalks, we did a special event. We were hosted at the Société Générale headquarters, in one of the most beautiful conference room I've ever seen. There also was more attendees than usual, and we gave some goodies, T-shirts and JetBrain licenses at the end.

It was also the first session with Antoine Pezé as our official new team member.

And for me, the first time I went to the SG building. I must say I had a bad feeling about the place at first. I feel like La Défense is really a creepy place, with everything I don't like about modern society. Big grey buildings that tower over you, and everything seems to have been constructed for giants. As a human being, you feel out of place. Big tall towers with thousands of people working in them, all dressed the same. The only sources of light were from the ads and the mall windows. Grey, work, consume.

But then, in all this ocean of sadness, we met with Adrien Blind who is in charge of organising the meetups at the Société Générale. And I discovered that the SG is actually much more interesting in the inside than the outside. They are quick to iterate, have DevOps all the way from top to bottom, and really know and apply Agile and Software Craftsmanship philosophy. We'll see more about that in the last talk.

The room

Front-end testing

The first talk was done by William Ong, former coworker from Octo. He presented the front-end testing ref card they developed. It's a physical cardboard flyer that lists all the different kind of tests you can do to your front-end (from unit testing to performance testing and security testing), with examples, tools and advices.


The content of the refcard is really really great. It gives a nice overview of what can (and should be done) today, but also advices on the costs of each of them and when to implement them or not.

The web frontend landscape evolved a lot in the past years, and it is getting more and more complex with more and more logic being moved from the back-end to the front. To keep it sustainable, we now need to use the same kind of tooling we're used to use on the backend: testing harnesses.

Unit testing are a must have. He won't even develop on that subject because it is obvious. No good quality code can endure the stress of time without unit testing. Code that isn't unit tested is not finished.

But then, came all the other kinds of tests. When should we use them? Which tools should we use? Are they really needed? All the other tests are harder to put in place, so you should only add them if it helps you fight a pain you already experienced. They are costly to start, costly to maintain, so the benefit must be higher than the cost.

For integration testing (here also named end-to-end testing or functional testing), you should only add them on the critical path of your users. The one that generate money (subscription funnel) for example. This kind of test will indirectly test the whole stack. It will warn you when the core functionality you're testing is broken, but won't really help you diagnose where the issue could come from (database, back-end, front-end, etc.). These tests are also the longest to write and will yield false positive whenever you update the design/markup.

Talking about design, it is also possible to test your design. Using PhantomCSS, you can take screenshots of your whole page or specific parts of it and check that they did not change with the previous commit. This will help you diagnose changes to the website created by a seemingly unrelated CSS commit. Those tests can be invaluable, but they will also yield false positive results when a design change is actually expected. As for the integration test, limit yourself to the real main parts of your app.

You can also test for common security exploits, like the top 10 OWASP. Some tools can test them on your website and warn you of any vulnerability. Another approach can also be to ask for a security audit, and I personally also recommend opening an open hacker bounty program, like HackerOne.

In the end, all tests share one benefit: they give you the freedom to make the code evolve without being afraid of breaking things. It gives you complete trust in the code.

It was William first public talk, and the room was quite impressive with more than 120 attendees, so I guess he freaked out a bit. There were a few silences where you could feel that William was intimidated, and he looked a lot at his slides to give him some assurance. In the end, the message was here and it was interesting, and we'll be happy to have him on stage another time if he wants.

How to win at TCG with code

I don't know how many coffees Gary Mialaret took before coming on stage for the next talk, but he seemed to be really happy to be here and was almost jumping and running while speaking.


Gary told all us about TCG (Trading Card Games), and how those kind of game are no longer really about trading (Hearthstone for example, does not allow trading of cards). The main common ground of all those games is that it's a duel between two players, where each player create its deck of cards before the game and must carefully balance the number of monster/spell cards (that can make him win), with the resource cards (that are needed for using the monster/spell cards).

Empirically, every hardcore Magic player knows that a balanced deck needs 24 resource card, but Gary wanted to get to the math behind it to prove that it was the most optimal number.

He introduced us to the hypergeometric distribution mathematical function, that can calculate the probability of drawing a hand with at least n "good" cards, given the number of cards in a hand, the number of cards in a deck, and the ratio of good/bad cards in a deck.

While applying the method to a basic Magic deck we do not get the 24 cards we talked about earlier. This is because this method does not take into account another Magic mechanism called Mulligan, that lets you discard all your starting hand and start with a new one instead. To simulate that, he had to resort to a bit more coding. He generated thousands of different hands, discarding them when they did not meet his expectation and managed to get back to the magical 24 number.

He went even further, simulating basic Magic rules, playing against what is called a goldfish (a player that does not respond to attacks, and basically does nothing). He went on creating adaptive algorithms, applying something similar to genetic selection on deck creation. He starts with simple deck, make them play against goldfishes, then keep the one that works best, apply a few random slight changed (a bit more of that card, a bit less of that one), and make them play again until he reached the best possible deck.

His final conclusion is that we should not hesitate to put some of our developer mind in action to solve things that are not related to development. The most important thing when we want to solve a problem, is to know which questions we're looking answers for. Magic is a very complex game, it is not possible to code every possible rule and generate every possible deck to find the ultimate one. But by focusing on one specific problem, we can learn a lot about the underlying principles and this, in turn, helps us devise a better deck.

How our brain reacts to instant

The next talk was done by Gaetan Gachet, with whom I work at Algolia. He talked about the way our brain reacts to instant feedbacks.


His presentation was explaining the theory of Information Foraging. The main idea is that the way we are today looking for information on websites is similar to what our ancestors were doing when hunting.

When you hunt you know a few interesting places where you know you might find game. But sometimes, not game shows up, so you wait a bit more. And more. And more. Until you decide that it is not worth waiting any longer, and that you might actually just move to the next place you know could be a good hunting place.

But this second place is far away, and it will take you hours to get there, so that's why you wanted to wait here a little longer. But now, you decide that your current spot is not good enough and you'll take the chance to move to the next one.

What happened in your brain was actually a simple equation of risks and return. At the start it seemed more interesting to stay, to see if you could find something here, because you know that this place should have animals to hunt. But the more you wait without results, the more you're thinking that moving to the next place might actually be more interesting. Until you decide that you've wasted enough time and actually move.

When looking for information online we act the same. We first go to a first website, because Google told us that it might have the information we are looking for. We are searching their list of products, trying to find the one we want. We are skimming pages and pages of results until we realize that what we are looking for is not here, and that maybe we'll have more luck going to the next website.

This would not have happened if either the first website let you easily find what you're looking for, or would easily tell you that it does not have what you're looking for. It is just a matter of how much information you get compared to the time you spend.

In that analogy, Google is actually the whole territory the hunter can access in a day, while each website is a known hunting zone. But because Google is so fast, moving from one hunting zone to the next is actually really easy. And so you are more easily convinced to try another hunting zone if you did not find what you were looking for in the first minutes or second of hunting.

The paradox here is that the faster Google is, the less time people will spend on your site, because they know they can easily go search in another website if yours does not yield relevant results quickly.

That is why it is very important to give quick and relevant results to user searches when they come to your website, because you have competitors, and users will easily jump to a competitor website if they do not find what they are looking for on your website. Being the top first result on a Google page search is not enough.

Culture Craft

Last talk of the day was a nice story about what happened at Société Générale in the past years, by Thomas Pierrain. Some people wanted to "wake up" the organisation. They felt like the overall strategy of the company was not adapted to its current culture. And that the current culture was slowly dying because of that.


The speaker actually confessed that he wanted to leave the company at that time. But he stopped short when he realized that his thinking was actually just something along the lines of "it was better before", which is what stupid old men are usually saying. And he didn't want to become a stupid old man, so he decided to do something about it.

He started organizing BBLs internally, where they will book a room during lunch and one of them was going to talk about a subject he was passionate about while the other would listen to him (and eat their lunch). They also organized some coding dojo, where everybody in a room would work on the same computer problem, one after another, and everybody helping others.

But it did not started that fast. At first he was alone. So he asked a friend if he would be interested in listening to him speak at a BBL. The friend was ok, and talked about it to other friends. So they did it. They did not tell the management, or booked a room. They just took an empty room and did it. They knew that because they were some of the oldest developers in the company, nobody would listen to them. So they just did it.

The first BBL was a success. The room was small, so not everybody could come in. Those who couldn't come in wanted to come to the next one. It started to work on a "first come, first served" principle and gave the event a nice image.

They also created some events codenamed "Dude, you have to see this!". In those events, they take a room and one person opens a Youtube/TEDTalk video he liked, everybody watches it, and then everybody discuss it.

And they kept creating things like that. Things like lunch mob, where they gather together for lunch and code on a project and push everything at the end. They posted photos internally, put some on Twitter and in the end, what started as a single initiative is now a well-known fact of how things are working at the SG.

His main advice was simply to make it happen. Some people won't like it, so don't invite them and don't try to convince them. Focus on those that are interested and build something for them and with them.


Overall a really nice session. Thanks a lot to the Société Générale to have hosted us in that wonderful room, and thanks for their very inspiring talk as well.

Unfortunately, even if the room had all the video capture capabilities, we still did not manage to get the videos... It taught us to always record with our own devices :)

Tags : #humantalks

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