Controller Testing

Recently I have gotten to work on a greenfield application, this has led to some discussions about the best way to test things. I personally have been taking time to write tests that allow me to take small steps giving me a better sense of direction. These small steps have allowed me to write a test, make it pass, write the next test, make it pass then refactor.

Continuously refactoring my code keeps it clean and maintainable. I’m not going for cleverness or golfing to the lowest number of lines of code. Instead I’m going for code that is flexible and allows me to continue to add new features with ease.

Below is an example of a controller test, written in two different styles. We’ll walk through a small refactoring scenario and see how we can keep our test simple and testing result rather than the implementation by comparing the two styles.

Disclaimer this example has some assumptions such as I am using FactoryGirl and Rspec.

Here is our starting controller, we are going to focus on the edit action. This is pretty strait forward, we’re going to edit an instance of ‘Foo’ so we’ll return it to the view.

class FooController > ApplicationController 
  def edit
   @foo = Foo.find(params[:id])
  end
end

One way we can test this is to build an object with FactoryGirl and then stub out the find method on Foo to return that object. This will allow us to test our edit action insuring that foo is always the same thing.

describe "GET 'edit'" do
  it 'should receive the STUBBED Foo instance' do
    @foo = FactoryGirl.build(:foo)
    Foo.stub(:find).and_return(@foo)
    get :edit, :id => @foo.id
  
    expect(assigns(:foo)).to eql @foo
  end
end

Another way we could test this trivial example is to just use FactoryGirl to create the object rather than just build it. This takes a little less code, but does require two hits to the database, one for saving the record and one for retrieving.

The benefit of this is we are setting up that if we send in the ‘id’ of ‘@foo’ we’ll get back an identical ‘@foo’ from the database.

Our controller test now is just saying hey we expect to get ‘@foo’ back, we really don’t care how you get it but in order for this edit form to work we need this ‘@foo’ back.

describe "GET 'edit'" do
  it 'should receive the NON stubbed Foo instance' do
    @foo = FactoryGirl.create(:foo)
    get :edit, :id => @foo.id
  
    expect(assigns(:foo)).to eql @foo
  end
end

Now let’s refactor our Foo controller to do something a little different. Now we decided that really the ‘@foo’ should be retrieved by sending the ‘@foo.id’ to a method called ‘by_bar’

class FooController < ApplicationController 
  def edit
     @foo = Foo.by_bar(params[:id])
  end
end

Here is our new class method that replaces the normal Foo.find.

class Foo
  def self.by_bar(id)
    Bar.find_by_foo_id(id).foo
  end
end

Now in our first version of the test we are going to get an error because we are not actually creating and saving the object and it is only stubbing out the find method making it brittle and tied to the implementation.

Let’s refactor our tests, first we’ll start with the test using a stub, we’ll need to modify the stub to use the ‘by_bar’ method.

Next we’ll look at the test not using a stub, this one does not need any work. Again we are testing to make sure that the instance of ‘Foo’ we are expecting is returned. In this case it is, so we don’t need to do anything.

describe "GET 'edit'" do
  it 'should receive the STUBBED Foo instance' do
    @foo = FactoryGirl.build(:foo)
    Foo.stub(:by_bar).and_return(@foo)
    get :edit, :id => @foo.id
  
    expect(assigns(:foo)).to eql @foo
  end
  
  it 'should receive the NON stubbed Foo instance' do
    @foo = FactoryGirl.create(:foo)
    get :edit, :id => @foo.id
  
    expect(assigns(:foo)).to eql @foo
  end
end

While looking at our refactoring we realize that we didn’t really need a separate method for our ‘Bar.find_by_foo’ and we can just move that into our controller like so.

class FooController < ApplicationController 
  def edit
     @foo = Bar.find_by_foo_id(id).foo
  end
end

Now our stubbed test breaks again, let’s see what it will take to fix it. We’ll have to change our stub again. This time the stub needs to be done on the ‘Bar’ class and ‘find_by_foo_id’ method. Again our non-stubbed test continues to work because we are still returning an instance of ‘Foo’

describe "GET 'edit'" do
  it 'should receive the STUBBED Foo instance' do
    @foo = FactoryGirl.build(:foo)
    Bar.stub(:find_by_foo_id).and_return(@foo)
    get :edit, :id => @foo.id
  
    expect(assigns(:foo)).to eql @foo
  end
  
  it 'should receive the NON stubbed Foo instance' do
    @foo = FactoryGirl.create(:foo)
    get :edit, :id => @foo.id
  
    expect(assigns(:foo)).to eql @foo
  end
end

As we have seen here taking small steps and limiting our stubs and mocks will save us time when refactoring. In all of these examples the things that broke the test were just breaking test setup code rather than actually failing the test giving us a false positive.

Using Virtualbox for development VMs

If you’re like me sometimes I just find it easier to use a Virtual Machine for doing development work, especially when it is a complex system with many moving parts.  Recently I started to work on a project that I had inherited from another developer.  The project was partially setup on a remote development server.  I wanted to under stand how the pieces went together and be able to pass it along to other co-workers, so I decided to build a VM.

I have been a heavy VMware Fusion user for many years yet not everyone in my office has the luxury of a license for it.  I decided to give Virtualbox a go for this project.

At first I was really happy with it, I got my machine up and running in no time and was working away until I came to setting up the server and realized for the sake of sane hostfile management I wanted it to have a static ip.  I decided to switch the network adapter over to NAT which is where the pain began.

I enjoy just shelling into my machines and working that way, once I switched to NAT I could not just shell to the ip address of the vm.  This seemed odd to me, VMware creates a virtual network for you which apparently Virtualbox does not.  So I went diving and here is what I found:

You’ll need to enable port forwarding to the vm’s NIC. To start open up the network configuration section of your vm.

The Virtualbox network interface menu

After opening the network tab, click on the “Port Forwarding” button under the “Advanced” section.

Then fill out the sections with the relative information.  I found that if you try and put in a Host IP the setup doesn’t work quite right.  Here I’m forwarding my localhost port 2222 to port 22 on the guest vm along with port 8080 to port 80.

Now from my host machine I can use the following shell command to ssh in $ ssh aip@localhost -p 2222 which will use the port-forwarding and let me access my machine.

The same logic applies to trying to view the site running on the vm, in my browser I just have to access http://localhost:8080.

Now this is a bit of work but it is the trade off for a free tool for virtualizing your environments.  It’s working for me right now but your mileage may very.

Pairing on a Severity 1 issue

Recently at work I had to help respond to a Severity 1 issue.  This is our worst case scenario, something major is broke in production and is costing the company money.  In the presentation I gave at Twin Cities Code Camp about pair programming I said that often troubleshooting bugs and fixing production issues weren’t the easiest to pair on.  Reflecting on the past couple days I noticed that while trying to fix the issue at hand we were pairing the whole time.  I don’t think we could have accomplished the fix without the entire team using some of the techniques I had outlined in my presentation.

We used two of my local pairing techniques along with two remote pairing tools. Locally we used a mixture of traditional paring and “Divide and Conquer” pairing.

Traditional

With traditional pairing one person is “driving” while the other person “navigates”. As I sat in the driver seat with vim open and tailing a log on production my manager sat next to me helping navigate through the code as we figured out what needed to be modified. I used to think that I liked to work on these high stress issues alone and troubleshoot things with my own process, but now have a different opinion.  Having someone there to limit the amount of thrashing was a major help.

Divide and Conquer

With a major issue there are lots of logs to check, experiments to try, and pieces of a system to update.  This is where we brought another developer so we could divide up the work and conquer the problem.  While I updated configs, he updated our applet code.  By the time I was done getting the configs ready he had the applet built and ready to be pushed out.  We were in constant contact sitting next to each other but were able to work in parallel to finish the one task.

Remote Tools

Working with a team distributed around the world makes troubleshooting major issues difficult.  I was able to keep everyone on the same page by using a combination of a screen sharing tool http://join.me and tmux.  I used Join.me to share a remote desktop session from London.  From the remote desktop I was able to use putty to connect to a tmux session on my own machine.  This way I could show code and logs to the entire team.  Using tmux allowed me to reboot the machine and pick up and start running very quickly.

Using pairing techniques and tools helped us diagnose the problem and solve it.

TCCC12 – Pair Programming recap

I recently I had the opportunity to share a passion of mine at Twin Cities Code Camp 12.  I gave a presentation, “Pair Programming Techniques”, where I shared my experiences of pair programing including things I found to great and things that are not so grate. This presentation was one of my favorites as it had a great amount of audience participation. I will attempt to share this information in a series of blog posts.

Pair programming is the act of working on a focused task with someone.  I’ve seen it be a productivity booster, we’ve all had times where we just hit the preverbal wall while working on something.  I always found that explaining my situation to someone else would help me get over this block and get back to work.  Imagine having that person right there working on the task with you. Sure I’ve been in situations where both of us in a pair got stuck but that is a rarity.

While pairing I tend to notice that I am getting a real time review of the code I am writing.  I like being able to discuss code while it is written, giving me a chance to learn and teach all while getting things done.

Pair programming is not the silver bullet, it’s not going to solve all your problems or make your team’s velocity jump a hundred and twenty percent.  It’s not just for twenty something hot shot developers, working at the latest startup.  Even though you have two eyes working on the codebase doesn’t mean bugs are going to get through. Pair programming is like the old saying “measure twice and cut once”, which doesn’t mean you are going to cut every board perfect but it it limits your possibility of a defect.

In todays work place it is common to have people in the office along with remote employees.  Just because someone works remotely doesn’t mean that they can’t pair and have to work alone.  There are advantages and disadvantages to both situations.

Pairing locally has many advantages, most of which have to do with being in a physical environment. When you are working locally you have the ability to better read your pairs body language, you can grab some paper and sketch out some ideas.

Sometimes pairing locally can have some distinct disadvantages too.  There are big things like sickness, working in a very close environment makes it easy to pass things to each other.

Working remotely solves the sickness issue and allows both people to pair and not worry when they have a simple cold.  I have found myself enjoying remote pairing in this situation.  While you don’t have some of the physical amenities that you would in a normal office setting, video chat and screen sharing comes pretty close. I have spent time working remotely at previous jobs and have found that human interaction is something that I need. Pairing remotely gives you someone to talk with, share your ideas and get feedback from.

While pairing remotely is great during the height of flu season, and with video chat and screen sharing you can almost see everything there is still a great deal of communication that needs to take place for the pair to be effective. Bandwidth is a major downfall of remote pairing, I live in a location with a slower DSL connection and I have to prioritize the tools I use when remote pairing.

Look for follow up blog posts about different styles and tools for paring locally and remotely.  I’ll cover some of the techniques I have learned and developed since I started pairing.

Slacking in November

I really wanted to write while I was on our trip but didn’t find any time to.  It was a nice trip to Phoenix and I was able to spend time playing with my camera.

Here are a few shots from my trip.

Ghost Trucks

Cactus Bowl

Soft kitty

From Above

Mad Railers – October 2011

Last night I had the opportunity to present again to the Mad Railers group here in Madison. My talk was titled “Writing, for love and money”. I took others along the journey I had while working on Web Development Recipes and some tips I learned from Brian Hogan, who is one of my co-authors and mentor over the years.

Some of my main points where:

Overall the main key to success is to work at it every day, because with practice we can all get better. So give it a go and if you need a boost check out PragProWriMo and start writing that book!

Cloning a site with Wget

The other day a co-worker was talking about moving some of his sites to a cheap static web host.  Most of the sites were either blogs, or CMSs that don’t change very often and don’t really need the overhead of a dynamic system.  I thought back about a script I had written to do this a year or so back.   The meat of the script was around a wget call which spidered a page, and then converted all the links to work with the new static documents.

wget --mirror -w 2 -p --html-extension --convert-links -P folder_to_save_to http://mysite.com

So with this simple shell script you can specify where you want to save the converted site by replacing “folder_to_save” and then substituting the site you want to clone/mirror in for “mysite.com”

There you have it a simple way to clone a dynamic site to a static one.

PragProWriMo

November is PragProWriMo or Pragmatic Programmers Writing Month.  Prags is promoting writing by tagging along with National Novel Writing Month.  They have setup a forum http://bit.ly/tTQgLF to help people track their writing progress and get feedback and support from other writers.

Since I just finished working on Web Development Recipes for Prags I want to keep my train rolling and keep writing.   So this month rather than working on a new book I am going to try and write every day.  My posts may come out in large groups since I will be on vacation 2 weeks out of this month but I’ll try to keep up the writing.

 

Ruby Koans

Recently after doing a Code Retreat with Cory Haines I found myself really wanting to work on my Ruby fu.  I was inspired by the idea of practicing my trade everyday in some simple exercises that  allow me to focus on parts of the language to really learn it well.

So I decided to pick up the Ruby Koans which I was introduced to a year or so ago but never thought I needed that.  I always figured I could just keep learning by using Ruby for my projects, but then I realized that I was just using the same few parts of the language to build my apps.

Following the craftsman analogy, I was using the same saw and hammer because they are comfortable.  I didn’t take the time to learn about the pneumatic framing nailer because I already had a way to pound in nails, but boy does it make building things easier.

So if you are new to Ruby or have been using it for awhile I really recommend you find some exercises to keep your skills sharp and explore new parts of the language. I really think the Ruby Koans are perfect for this, I see them being easy to get started and with enough substance that even seasoned developers will pick up new things.

Web Development Recipes

Today marks a new accomplishment in my career.  I am a published, professional author.  Today we released the beta of Web Development Recipes a book for anyone interested in expanding their knowledge of Web Development.

I worked on this book with several very intelligent and amazing co-authors: Brian Hogan, Chris Warren and Aaron Godin.

So head over to http://pragprog.com/book/wbdev/web-development-recipes and pick up a copy, or two, or three!

Web Development Recipes Cover