Rantings of Dan

[dangalipo-blog]

I'm a real boy now

I have just started as a full time Frontiersman after a long 7 years of finishing off a Computer Science degree(I hope). I've been through a week and its going really well; the people are awesome and I'm learning a lot.

Something I told myself was that once I started full time I really wanted to push myself as a developer. I figured one good way to help consolidate things that I am learning is to write a weekly blog post about things I found of particular interest in the previous week. So here are what I hope are the first of many posts to come.

Bogus Gateway in Active Merchant

The first thing I want to talk about is the BogusGateway that ActiveMerchant provides. I had done some work previously with Active Merchant but this was the first time I had come across it. Basically, it gives you a gateway which allows you to test with without having to actually hit a banks api with a test account or stub out all the calls. Generally you'd set it up something like this:

module Example class Application < Rails::Application ... @@CreditCardGateway = ActiveMerchant::Billing::Gateway.new end end

Example::Application.configure do ... Gimme::CreditCardGateway = ActiveMerchant::Billing::ActualGateway.new(:login => 'RealMerchant', :password => 'password') end

Example::Application.configure do ... Gimme::CreditCardGateway = ActiveMerchant::Billing::BogusGateway.new(:login => 'TestMerchant', :password => 'password') end

You then pass it a ActiveMerchant::Billing::CreditCard object with a number of 1 for valid or 2 for invalid (anything else throws an error). You can then make calls on the gateway like you normally would. The only small issue with this is that 1 and 2 aren't valid credit card numbers so if in your method you check that the card is valid (as you should), you will need to stub the call to valid? out.

Has many through through

This is something that caught me last week. I had the following associations. 

class Airplane < ActiveRecord::Base has_many :airplane_remotes has_many :remotes, :through => :airplane_remotes end

class AirplaneRemote < ActiveRecord::Base belongs_to :airplane belongs_to :remotes end

class Remote < ActiveRecord::Base has_many :airplane_remotes has_many :airplanes, :through => :airplane_remotes end

class Battery < ActiveRecord::Base belongs_to :remotes has_many :airplanes, :through => :remotes end

If you call battery.remote.airplanes you will get the list of airplanes that are associated with its remote. If you call battery.airplanes you get an empty collection. In anything below Rails 3.1 you can't have a has many through through relationship.

Active Admin f.has_many

I also had the chance to play around with ActiveAdmin a bit last week and was very impressed with it. One thing that I was really impressed with was the nice little addition to the Formtastic form builder it has. What it allows you to do is specify a has many relationship in the following way.

ActiveAdmin.register Example do ... form do |f| f.inputs do f.input :name f.has_many :programs end f.buttons end end

This will use ajax to create new program associations without having to refresh or write any custom javascript. You need to make sure that Example accepts_nested_attributes_for :programs otherwise it won't work One slight drawback is whilst it will allow you to destroy any newly created associations, it won't allow you to destroy any pre-existing ones. Even so, I found this really neat.

As I think I've said before a lot of the topics on this blog aren't ground breaking stuff but I figure it might be useful to people who are learning like I am.

Stay tuned for more updates. 

[dangalipo-blog]

Dangers of over mocking and stubbing.

I was writing a test the other day and I hit a realisation as to why over stubbing/mocking can end badly. 

The code I was writing the test for looked  something like this:

Class Person

.... def good_friends

Friend.where(:person_id => id, :good => true)

end

After seeing that I was going to write a test that looked something like this:

describe 'good_friends'

before:each

@friend = Friend.new

@person = Person.new

stub(@person).id { 1 }

stub(Person).where(:person_id => 1, :good => true) {[@friend]}

end

it 'should return all the good friends' do

@person.good_friends.should == [@friend]

end

end

However before I started to write it I realised I could refactor the code to look like this: 

Class Person

.... def good_friends

self.friends.where(:good => true)

end

Then it hit me; the test I was about to write would now fail even though the overall functionality of the method hadn't changed. By stubbing out the where clause rather than using real data from the db, I had made my test very brittle. 

Now I'm not saying you should never mock/stub or that you should always hit the db, but its something keep in mind when writing your tests. Perhaps ask yourself "If someone else implemented this function in a different way would my test still pass?".

Dan Out

[dangalipo-blog]

Dragon Age 2

This week I was struck down by a few various plagues, so this weekend is going to be spent catching up on uni and work. One thing I did achieve this week was to purchase and finish Dragon Age 2.

Sadly, I was very disappointed with the sequel to Dragon Age: Origins. Now I'm not saying DA2 was a bad game in its own right, in fact, I think its quite good compared to a lot of console rpgs, but it just doesn't compare to its predecessor. I say that for a few reasons.

Firstly, there are no non-combat skills, at all. The one I really missed was the coercion. In DAO having high coercion or other skills opened up different conversation options and from there, different ways to deal with situations which was awesome and in fact, has been a staple of most Bioware rpgs. Not so in DA2, you generally get the 3 same ways of dealing with a situation: the nice way, the sarcastic way and the aggressive way. Also each one of those options has an icon which tells you which one you are using (just in case "you die now!" wasn't obvious to you).

Secondly, while on the topic of conversations, lets talk about romances. Now Bioware has done an excellent job of promoting equal opportunity gaming in that, as I played through as a male character I could choose to pursue a relationship with a male or female npc. I applaud this, I don't see why you shouldn't be able to play any sexual preference. The thing that got me was that DA2 beat you in the face with it in that, I had to actively try to not end up pursuing a romance with another of the male npcs. What I mean by that was, there was one character who I was generally being supportive of then suddenly he said something like "We should definitely make out". Hang on wait... what just happened?!? Apparently me suggesting that you and your kind shouldn't die in a fire was a green light for some bromance. But whatever, maybe the guy was lonely, but I wanted to politely let him no I wasn't interested so I didn't lose the friendship points I had with him (high friendship unlocks abilities).  My options were: make out, sexual innuendo or I wasn't interested. I selected not interested. My character proceeded to do this in the most aggressive way possible. This shows another example of how the DA2 trinity of conversation choice fails.

Next, I'd l like to take a moment to talk about questing and the story, without giving away too much to those who still want to play it. My main gripe with the story was that it felt quite linear in that, with the main story after each act you jump at least a year or two into the future and what you did doesn't seem to effect what happens after that. It also got hard to get immersed into because you were always jumping around after each act. DA2 also introduces random quest items. During the course of the game you, pick up a lot of junk items (you know to clog your inventory, because thats what every good rpg needs, bag filler... not) but, you can turn some of these into random npcs in the world for free money and xp. This seemed sort of pointless and generic in that, no matter what you return, to whoever you return it to, your character will say "I think you lost this" and they will say "thanks".

Finally a brief note about the pc version. When I got it i did what i do with all my games; crank graphics settings to max! When I did this with DA2 however it was unplayable. After some reading I found out it was an issue with DX11 rendering and you could either get some beta video drivers or use DX9 rendering. I did the latter. Granted it was just me being lazy but it always saddens me when a game is released with major technical issues.

To conclude, it may sound like I'm saying that Dragon Age 2 was a horrible game. It's not; I did enjoy the game overall and its not a bad rpg compared to other console rpgs, but Dragon Age: Origins was the best pc rpg since Baldur's Gate 2 back in the 90's, and Dragon Age 2 just didn't compare and seemed like it was a game based on the original, not a sequel.

Dan Out 

[dangalipo-blog]

Have to start somewhere.....

Hey All,

I'm Dan and I'm a Rails developer working for The Frontier Group. I had been a little resistant to starting a blog because I've only been developing using rails for about 18 months and I figured there are a lot of far smart people with far more experience posting on the subject. However, I also thought maybe there are developers who are learning rails and might find some of my experiences useful. It also gives me a chance to voice my opinions that I can't condense into 140 characters. I guess I should kick this off with something i've learned recently; writing custom validation in rails.

I know this is nothing new but I found out about it the other week. Basically rails gives you the ability to write a method which tests a condition and attach an errors if it does not pass the condition. For example, you have a tree structure perhaps describing movie genres and sub-genres and at the end of each branch the bottom node has many movies attached to it. One condition you might have is that only a bottom node can have movies associated with it. Now lets say you want to prevent people from adding a new node in the tree beneath one that has movies associated. You can achieve this with something like the following code:

Class GenreNode < ActiveRecord::Base ... validate :parent_has_no_movies ... def parent_has_no_movies if self.parents.any? if self.parents.first.movies.any? error.add(:parents, :parent_has_movies) end end end end

You then have to add the error message you want to your translation file and thats it. If you try and save an node with a parent that has movies attached it will be invalid, not save and produce the validation error you have specified.

One thing to consider when writing these methods is to remember that you have them when writing your tests. You may find some of your tests fail because your test object or associated object might not be in a realistic state. The easy way around this is to stub out the custom validation method you wrote, however, you should be testing with valid data and if you have to do this you should be sure that your not creating holes in your code coverage by doing so. 

Hope someone somewhere finds this useful.

Dan out.