First week of the 2012 CIM Ruby class
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Week 1


The objective of these exercises are to set up tools and processes that you will need to be an effective Ruby developer. Quickly scanning the tasks that lay ahead you will get the distinct impression that the majority of your time is not actually learning the Ruby language. That is indeed an accurate observation (+1 point). This is not an oversight.

It is important to take the time to become acquainted with a number of great time saving tools. As well as starting to reach out to the development community. Trust me that the efforts spent here will help build skills that will come to your aid in short amount of time.

Despite all this non-Ruby business there is a portion where you will actually start to learn Ruby syntax. So never fear you'll write some delicious Ruby code this week!


Complete the following sections:

  • Sharpening Your Weapons
  • The Kingdom of Github
  • The Land of Ruby

The additional exercises in the exploration section are for those interested in spending a little more time within these areas.

Sharpening Your Weapons

Before preparing for battle it is important that you have steeled your nerve and sharpened your tools. With software development you must do the same. Before we enter into the vast land of Ruby, you must be prepared for any chance encounter.

The following exercises involve a lot of software installation. With that comes a whole host of new problems as every system is different. In some instances this may already be easy or already completed. In others this may be your undoing. I implore you to stay with it and know that we are all here to help you make it through.

Install Git

Git is a distributed version control system. This is an essential tool to ensure your work is saved and versioned successfully.

An optional 'Exploration' exercise below encourages you to return to learn more about git.

Github outlines installation instructions which tell you to install Git from the source. I would recommend that you take the plunge and install Homebrew.

/usr/bin/ruby -e "$(curl -fsSL"

Brew will allow you install multiple different programs very quickly and easily.

brew install git

Install RVM

Ruby Version Manager (RVM) allows you to install multiple ruby versions on your system and switch between them easily. You may be asking: Why am I worrying about multiple different versions of Ruby when I don't even know how to program in one? Great question, you sure are smart!

Even if you are only going to use one Ruby version it is still important to ensure that you are familiar with a tool that is a community standard. It also makes it unbelievably easier to update and upgrade in the future.

Launch Terminal. This will allow you to run the commands to install RVM.

Install RVM through the following command:

$ bash < <(curl -s

Then install the RVM script to your ~/.bash_profile:

$ echo '[[ -s "$HOME/.rvm/scripts/rvm" ]] && . "$HOME/.rvm/scripts/rvm" # Load RVM function' >> ~/.bash_profile

Now close your current Terminal and launch a new Terminal.

Install Ruby 1.9.2 and make it the default Ruby for your user.

$ rvm install ruby-1.9.2-p290
$ rvm --default use ruby-1.9.2-p290

The Kingdom of Github

Github is an easy, and free (as long as what you are doing is public) way to share code and collaborate with others. It's like the Facebook of software development.

Accounts are free for all the work that we are doing and your account will likely be free for as long as what you are doing does not need to be private.

An 'Exploration' exercise below encourages you to return to learn more about Github.

1. Create a Github account


2. Create a SSH key and Upload it to Github

After the git instructions for Mac there are instructions about generating and uploading your SSH keys to Github.

3. Message me trevmex.


4. I will add you the CIM-Ruby organization

As well as individual developer accounts, Github offers organization accounts. We are using the CIM-Ruby organization for this class. However, any other work you want to put on Github would not be part of this organization.

5. Fork and clone this repository

Any user can fork and clone any public repository. That means you can very easily create your own personal versions of anything that someone else has created (e.g. like linux).

Now it is time to fork this repository. There is a Fork button at the top of this page that allows you to make a copy of this repository.

Instructions on how to Fork and Clone:

When you fork it, a copy is made that you have the ability to augment. By forking the assignment you can make changes to your version, while the original version owned by me remains and unchanged.

Advanced Features of Git

The Land of Ruby

Move yourself into the project directory that you have just recently cloned.

It is with great pleasure that I welcome you to the Land of Ruby. What lies ahead are again very deep, rich tools (read: COMPLEX). Again, these are tools that will serve you through the next few months of Ruby development so it is important to present them to you first very simply.

Do not be discouraged if again you feel as though you are simply following steps without any understanding. You will do this again and again.

1. Install Bundler (gem)

gem install bundler

Bundler is a library that takes care of installing all the remaining, necessary libraries (gems) for a project. This assignment requires a number of ruby libraries (gems) and instead of having you enter all those in, Bundler will take care of it for you.

2. Install all the remaining gems


Executing bundle will take care of installing all the remaining gems that this project requires.

3. Run the tests

The tests for this project are written in a Ruby test library named RSpec.


NOTE: If rake fails to work you may have to execute the command: bundle exec rake

4. Setup a guard

When you're trying to solve problems or simply exploring the Ruby language it becomes tiring having to: write code; save code; and run the the tests. Thankfully other developers understood that and put together a library (gem) called Guard. Guard will watch to see when test files are saved and re-run the tests for you automatically.


5. Fix the broken tests

Within the tests that have executed several of them are passing but a few are broken. It's mighty morphing Ruby time!

Within the examples provided there are several working, positive examples divided into different types. Open one of the files and look within the output from Guard and see where that information is being presented.

All of the failing examples can be found in the file spec/failing_spec.rb. This is where you will get your hands dirty.

  1. Identify the failures
  2. Identify where in the failure information what is the file and what is line number.
  3. Go to that file and line number
  4. Fix the issue.

With Guard running any change you make and save will cause the system to re-run the tests. There you can watch to see if the number of failures decreases. Your goal is to have 68 examples, 0 failures. Good luck!

6. Save your changes

When you have finished fixing the tests it is time to save your work with git. What follows is a series of commands that will save your files.

git add spec
git commit -m "Fixes to the Broken Tests"

7. Share your changes

With your files saved (committed), you can copy those changes to your repository on Github. Creating a copy of them on an external system, allowing you to: recover them if you were to delete them locally; start work on another system; or share your work with other people.

git push origin master


Congratulations. If you have made it this far you have completed all you had to accomplish. But I'm sure that you likely have burning questions or would like to learn more about a particular technology or Ruby. This is your chance...

Learn more about git

Git is complex software.

Spend some time learning more about git. Read through at least the introduction on the first page. If you're still following follow the link at the bottom On to Getting and Creating Projects » and continue reading until you've had your head is swimming or it's put you to sleep.

There is no requirement that you complete anything; just look around.

I assure you that the more time you spend here trying to understand or learning, the more amazing you will be in the rest of the development that you do.

Please note that since this class is not about Git we have to avoid getting side tracked by the many complexities of Git. So dig deep, but we'll just use the basics in class.

The commands you will need to understand before you start to feel comfortable.

git clone
git status
git log
git add
git commit
git pull
git push

Inevitably you will find yourself stuck once or twice and unsure what to do next when working with git. Well, here's what to do:

  1. Just ask or search for help. Undoing your most recent action is usually very simple. (But you'll want to get the undo right!)

  2. Go slow. Run git log and git status a few times. Think about the git workflow.

  3. Until you are somewhat proficient, if you get really stuck it's better to start over. Simply save your code off somewhere, clone a clean repository and start over practicing a clean git workflow.

Learn more about github

Return to the Github Help Section.

On the right-hand side there are several sections of content starting with the labels Beginner, Intermediate, and Advanced ... . We have accomplished quite a few of the Beginner exercises during our travels. Take some time to explore these sections. If you find something that makes sense and moves you then give it a try. There is no requirement that you complete anything; just look around.

As Github has become the cornerstone of the open-source software development in recent years, I implore you to spend some time cruising around the Facebook of software development.

Think about a text editor

It's a big step and I am sure you will want to talk to your parents, older siblings and any religious figures that provide you guidance in making this decision. It is not one that I can make for you.

While many will try to persuade you to join their particular text editor cult, I want to stress to you the most important thing at the moment is to pick an editor that will not make you pull the rest of your hair out (or someone else's hair).

Select an editor that gets you most of the way there. After awhile, when the dust has settled take the time to look around and start asking yourself how can I be more efficient, loved by my fellow hackers, etc...

The following editors are simply suggestions:

Explore Ruby through RSpec, Rake, Guard, and Bundler

Bundler, Rake, Guard and RSpec are all written in Ruby. Yet they all have very different syntax. This can often times lead to confusion to those of new to the Land of Ruby. Under the sheets they are using some of the more advanced features of Ruby to make it the code written more clear and to the point.

The following exercises spend a moment with each. Don't feel like you need to explore each one or explore just one.


RSpec speaks in the languages of describe, context, and it. You also may have noticed a lot of the word should. This is the Domain Specific Language (DSL) of Behavior Driven Design (BDD).

While describe and context syntactically are not very different, save for the restriction that context cannot be used as a top level element within a spec file, it is often good to use context in situations where a group of tests are illustrating a particular state.

describe "Client" do
  describe '#connect' do
    context 'when the server is available' do
      it 'should connect to the default server' do
        # ... example to test the connection

    context 'when the server is not available' do
      it 'should raise an exception' do
        # ... example that tests throwing an error 
  • Try replacing describe with context in every instance.

  • Try replacing every use of context with describe.

When you state an expectation in the test you are using RSpec's matchers. This is that bit of code hanging off of the value you are testing .should eq(expected) or .should be_kind_of(NilClass).

  • Take a look at some of the built in matchers and try using a new one to make a failing expectation.

  • Try using a new one to make a passing expectation.

Strings, Symbols, Booleans, and Numbers, oh my!

Even though you completed the assignment by fixing all the broken tests you could return to the tests to learn more about the classes that you quickly came to understand.

Using as a resource try to define your own tests for one of the following classes:

Strings have methods for all kinds of operations that may prove useful to you in the future (e.g. splitting, replacing, and trimming).

Integers and Floats are a mainstay of any language. The Kane to the String's Abel. Often times you will want to increase a value by one, find out if they are even/odd, or round to the nearest value. How do you do that in Ruby?

Symbols are strange beasts if you have come from other programming languages. If you aren't sure what to make of them, perhaps you could spend more time with them or figure out how to turn convert them to things you know what to do with.

Nil is like a manticore or a liger. Everything is one at some point, until they are assigned something but they they have things that they can do. What happens when you convert one to a number or string?


Rake speaks in the language of task. A task makes it easy to execute operations with just a name. First experiencing Rake you notice that by simply typing the command rake you essentially typed out rpsec spec/*_spec.rb. rake is by far easier to remember and hides behind it the complexity of what is going on when you execute your tests.

  • Execute rake spec

This is the same as the command rake. Why is it the same? What makes it the same?

  • Try changing the name of the rake task rspec

Try executing the command rake. Does it still work? What happens when you specify a different value for as the default.

  • Try creating a new rake task

  • Try changing the default rake task to your new rake task

  • Try changing the rake task names from Symbols to Strings

The tasks :spec and :default are Symbols. Do the tasks still work when you change them to 'spec' or 'default'?

  • Read about the system method


Bundler is a dependency management tool for Ruby. The benefit of defining this Gemfile is that when you share the program with others this will describe all the libraries (gems) that are required.

  • Try adding a new gem to the Gemfile

You can add almost any gem as a dependency to your system. Go to and select one of the gems listed in either of the sections: New Gems; Most Downloaded Today; Just Updated.

Click on the gem name and scroll down until you see the section titled Bundler. Copy and paste that section into your Gemfile. Run the command:

  • What is dependency management?
  • Why is it useful?
  • Is it similar to other dependency management systems you have used?