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Craftsman Swap Day 4 - Oh how fast a week goes, especially when it's short.

by: eric | June 24th, 2010 | 1 comments »

Did you know that Midsummer is arguably the biggest holiday in Sweden? And did you know it’s celebrated tomorrow? And that there’s no work tomorrow? Neither did I, and neither did CJ otherwise he probably would have tried to schedule this for a different week. Originally it was scheduled for the middle of July, when I am unavailable because of the imminent birth of my son. In fact I’m not really able to do a craftsman swap from oh..now…until the end of this year when the new baby might be old enough that I could leave my incredibly understanding wife at home alone with 5 children with a clean conscience. So really I have to thank CJ for forgetting a national holiday so that I could have this fantastic experience.

In celebration of midsummers we had what we Americans call a Pot Luck and what the Swedes call a “llAHHRdcdfagageeees”. I really don’t have the language down, but I’m sure that’s pretty close. We got to eat out on the veranda and I ate some pickled herring! Despite being warned I actually quite liked it and the view of the “lipstick” building is fantastic. Plus the eLabs folk (and @keavy - in yellow) are great people so you’d be pressed to beat the company. I’ll have a full post-mortem tomorrow ( as well as a special bonus post I’ve been sitting on for a few weeks) so let me just take this opportunity to thank 8th Light and Elabls for a great week. I’m honored to have been chosen for such a trip, and I hope I was able to give back a little of what I was given.

Now hopefully tomorrow I survive the insane bicyclists.

International Craftsman Swap Day 3

by: eric | June 23rd, 2010 | 0 comments »

After attending tonights got:ruby I became obsessed with and started installing rvm. It worked swimmingly, and I’m looking forward to getting my development machine off of the embarrassingly low version of Ruby and experimenting on the latest versions without (unintentionally) screwing up my production environment. Indeed after this week I’ve got a lot to google, lookup, and research. I’ve decided I have got to get good at JQuery - probably using it on a small Rails 3 project in the near future - and learned that Jasmine has it all over ScrewUnit. This may mess up my Haskell plans - not that I’ve ever messed that up before. After that we played a lot of ping-pong, then I decided to clean up my hard drive, because it was really time. Then I realized if I’m gonna do this project as Rails3, I better make sure I can deploy it on dreamhost with bundler.

If this sounds like procrastinating it’s cause it is. I also checked email, read Anders’ blog on the elabs.se site, and watched some of Germany beating Ghana. None of this is writing the blog post and that’s because today’s blog post is going to be hard. Let’s get this out of the way first. Today was another great day at ELabs. With my Jet Lag finally kicked I really was able to contribute, using a couple ideas we’ve had before on 8th Light projects to get some cool work done on the project I’ve been working on this week. I even wrestled for the keyboard a bit (although they have two keyboards - so it was lonely, I wrestled with Pixie) then we topped it all off a cool Ruby user group meeting. The meeting was last minute, so they had lightning talks where CJ talked about Bundler and rvm, Jonas talked about a Javascript testing plugin he’s working on, we puzzled over a problem one of the other developers was having and even looked at Omni Graffle. Now that I’m awake the ELabs guys had to suffer my jokes like the 8th Light guys do all the time. Now they know why they sent me out of the country.

What’s been really nagging at me has to do with the way that the ELabs boys work. See they are what Brian Marick would call “classicist” TDDers - they essentially never use mocks. I on the other hand generally mock out a lot. What Jonas said to me was, and I’m going from memory here, “I’d rather the tests run slow than be right.” Of course taken as stated, this is a truism. Nobody is voting for slow tests, although I might argue that the tests that verify correctness are often different than unit tests, and that unit tests are verifying a different thing. Aside from speed mocks provide value in designing apis by letting you design it with a client using it, before the object itself exists, and in thinking of systems as objects passing around messages you can really focus on their interactions instead of the implementation details. Mocks lead to a cleaner design all told….except….

Except I usually stub out things for speed. Objects I’m stubbing are webservices, database objects, file access, etc. And in the best cases the benefit I get is speed, and in the worst cases I get a tangled mess of mocks where my code and tests are coupled, but nothing necessarily works. I’ve completely traded speed for correctness. Why is that? Why am I not getting all the purported benefits of mocking.

In a related note on the way here I started reading “growing object oriented software, guided by tests” by Steve Freeman and Nat Pryce. In a throw away comment they say, “Never mock out third party API’s, write thin classes that wrap those with integration tests, and mock out your objects interaction with those classes.” Now maybe you think you haven’t done this, but let me give you some typical examples of mocks:

• IO.stub!(:read).and_return(mock_file)
• ActiveRecord.should_receive(:find).with(1)

Well look at that - those are two third party API’s aren’t they? And they are often mocked out everywhere! Trading speed for correctness again. “Okay fancy boy”, you’re saying - and really why are you calling me that, “Then we shouldn’t use mocks. Problem solved.” Not so fast. Have you ever had the problem where you are testing that an object gets saved and you do this:

object.should_receive(:update_attributes).with({:my => value})

but then you think, “Gosh I really don’t care how they save the values, I just care that it gets saved.” Right now you have to call update_attributes to make this pass, but you could call update_attribute, or set the object and save!, or hell use SQL although you shouldn’t. This makes for a crappy test - one you’re likely to break then fix later instead of changing in the deliberate process of TDD. What if instead you did this:

object.should_receive(:update_my_value_to).with(value)

Of course the other things are still true - assuming it’s an active record object, but maybe it’s not. Maybe it’s a wrapper around it, or maybe it’s datamapper object, I don’t really don’t care. I’ve gone ahead and mocked this call because that’s the call I really want to see - and somewhere else I’ve test driven that call against the database. Now let’s imagine you’ve got more complicated scenarios. Ever done this?

object.should_receive(:get_this).and_return(object2)
object2.should_receive(:is_true?).and_return(false)

This is a simple example - but I’m sure you’ve seen worse. The problem is again that you really need one method, maybe two, but you probably figured out in your head the algorithm beforehand, then test drove it. Maybe you know if object2 was true you needed to set unrelated object3’s flag - so you started writing those tests. Let’s look at that rule again though - don’t mock a third party API. Well what defines a third party API? Is it a third party if another company wrote it? How about the same company - but on a different project? Or the same project but a long time ago? Or YOU six weeks ago and you forgot it. Isn’t it a third party API again? What’s the difference? Should you then mock out objectnew - and test drive it with real objects? Because it’s pretty clear the API you want doesn’t exist yet, and that’s the crux of my long wrambling argument that I’ll probably better express and codify when it’s not late and I’m not tired:

Stop mocking the API you already have - mock the API you need

And then if by chance it matches the API you already have - by all means just substitute the real object in. But write the implementation with mocks first - without using any real API unless it matches coincidentally. Pretend the object doesn’t exist yet, and then mock. And maybe then you’ll get what you’re looking for.

Eh - or maybe I should go write some Javascript.

International Craftsman Swap Day 2

by: eric | June 22nd, 2010 | 2 comments »

Before I get into some of the details of day #2 at eLabs, let me dispell a few myths about Sweden that my American readers may still believe.

Swedes buy all their furniture at IKEA

This is of course a silly idea, caused by the prominence of the IKEA brand in the United States. In fact IKEA accounts for a mere 83% of the furniture market here in Sweden, with the rest of the furniture being bought at independent specialty stores such as Wal-Mart.

Ski jumping is the primary form of transportation

Swedes have a wide variety of commuting options available to them. By far the most popular is to bike to work at speeds of upwards of 300 miles an hour, using the bodies of pedestrians to slow your bike down when you arrive at your office. The speed is necessary to outrun the second most popular form of transportation, the electric trams. The trams take a convenient route to your office, assuming they don’t fly off the tracks. Which they do, often. Ski jumping is naturally third, keeping the commuter safely above the trams and bikes, until they crash down on the brick sidewalks. Finally I believe two gentleman own cars, but they rarely drive them because they are afraid.

The Swedish Chef is President

Don’t be an idiot. Sweden has a Prime Minister, not a President.

With that out of the way, we can properly concentrate on my time at eLabs. I promised yesterday I’d document stand-ups the eLabs way, and I’m glad I did because today I got to see first-hand day 2. Standups at eLabs go something like this - everybody stands up from all projects. There’s about 8 employees, so it’s sizeable but not gigantic. On Mondays everybody gives an update for the project they are on. The rest of the week everybody just pipes up if they have a problem. What I find interesting is there is no customer involvement - these stand ups are for team members to team members - and the multiple project nature of the meetings doesn’t seem to slow them down at all.

From there they retire to pairing stations and it’s a lot quieter than the 8th Light office - especially since I’m not at the 8th Light office making noise. They have offices where the pairs work, which I find both good and bad. At 8th Light on fridays we have frequent problems where one pair is on a conference call and another is animatedly discussing a problem, so that would be helpful, on the other hand there’s definitely an energy to everybody in the same room that isn’t there when offices have doors. It’s an interesting hybrid approach, and I could get used to it.

On a personal level I wasn’t 100% today. I woke up at 4:45, apparently Jet Lagged, and learned that Gothenburg doesn’t have early morning coffee shops for iPhone hacking. After walking around the rather cold town for over an hour I finally found one at 7:30, and thought I was fine. At two I crashed, and was completely losing concentration, practically falling asleep in my chair. Fortunately they have ping pong and after a couple quick games I was back to my normal self, and really wrote some code. I really want to get better at JQuery and ScrewUnit, because right now I’m still coding too much Javascript by luck.

Afterwards Jonas was kind enough to join me for dinner and we had a lively conversation about mocks and when (or when to not) use them, as well as the way eLabs does their Rails testing. I’m too tired to properly write my thoughts now, but it’s definitely gonna be a blog post tomorrow. It was a very nice dinner and I’m glad Jonas joined me. Now if you’ll excuse me I have to dodge the death trams on my way back to Andres Apartment.

International Craftsman Swap Day 1

by: eric | June 21st, 2010 | 0 comments »

Today was day one of my Craftsmanswap with eLabs developer Anders Tornqvist, and so far they have treated me with the hospitality and graciousness I expected. Largely they’ve been led by my pair, pictured at right. This is Pixie, who’s been working in the same room as me all day, and when she hasn’t been barking at me she’s been growling. It’s been a tad….terrifying? Especially when the blood is dripping from her teeth, and she can leap so high!

Actually poor Pixie had a rough time of it last night, and it apparently led to her being out of sorts. She eventually got along with me just fine, and I was able to have a productive day pairing with Ingemar. I hope I was helpful, as I’m trying to spend most of my time listening. I hate being the guy who shows up on a project and immediately tells people how to do stuff, plus Ingemar had a grumpy boxer/pit-bull mix next to him so I wasn’t gonna ruffle feathers. The problem with that approach is that you can end up failing to contribute by being too passive, but I think I did okay today. Tomorrow I’ll probably be a little more vocal, and moreso the next day. You know, just in time for me to leave.

The highlight of our day, for me anyway, was implementing drag and drop in JQuery. I’ve never done it before - I think I’ve done it in Prototype but it’s been a while - and it’s amazing what a breeze it was. I’m going to have to find an excuse to use JQuery more, and I’ll probably try and find out some info on ScrewUnit. Of course on the plane I started reading “Growing Object Oriented Software, Guided by Tests” and a new iPhone book, so I’m nothing if not capable of overbooking myself. Speaking of which GOOS looks like a real winner, if you didn’t already know.

In addition to some JQuery at one point or another Ingemar touched on a gem or idiom I wasn’t familiar with, often with me hurriedly scribbling notes probably without him realizing it. The list of gems from today alone was:

• formtastic
• hitch
• machinist
• launchy
• carrierwave

Hitch was seriously cool, allowing us to push git changes as a pair. Formtastic is an interesting form builder, and although we had some struggles with it today Ingemar assures me it’s awesome. It did have a nice DSL syntax. We used machinist’s blueprint feature for building factory objects, kinda like factory girl. I admit I like the concise syntax, but I wonder if we should be making it easier to create lots of objects in setup for a test. Launchy cleanly launched the browser when testing at a given point, and finally I’m excited to use carrierwave for file uploads tomorrow.

I have more notes, particularly regarding the different way that eLabs does standups, but I fear this blog post has become disjointed and a tad dull, so I shall leave you until tomorrow.

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