Ruby Calisthenics

The goal of this multi-part assignment is to get you accustomed to basic Ruby coding and introduce you to RSpec, the unit testing tool we will be using heavily.

While we provide an explanation of how your code should work in this handout, you should get accustomed to the idea that the true specification is in the test files!

Therefore, we suggest you work on this assignment using autotest, which automatically re-runs all the RSpec tests each time you make changes to your code:

1. In a terminal window, change to the root directory of this homework (the one containing subdirectories lib/ and spec/) and run the command autotest. RSpec expects to find code files under lib/ and the corresponding spec files under spec/.

2. Initially, all tests are marked “pending”, as indicated by the argument :pending => true in each describe block. To start working on a question, remove this option:

    describe 'palindrome detection', :pending => true do

to

    describe 'palindrome detection' do

and save the spec file. autotest will detect the change and automatically re-run the tests in that group, which will now fail (displayed in red) since you haven’t written any code yet.

3. As you fill in code in the appropriate files under lib/, each time you save changes to that file the tests will automatically be re-run. When a test passes, it’s displayed in green. Your goal is to get all tests for all parts to pass green.

(Note: when you submit your assignment, we may also run additional test cases beyond the ones ls given here.)

Exercises

• Part 1 Fun with Words and Strings
• Part 2 Basic Object-Oriented Programming for Dessert
• Part 3 Rock-Paper-Scissors
• Part 4 Ruby Metaprogramming

HINTS:

• Don’t forget that the very first time the attribute receives a value, its history array will have to be initialized.
• An attribute’s initial value is always nil by default, so if foo_history is referenced before foo has ever been assigned, the correct answer is nil, but after the first assignment to foo, the correct value for foo_history would be [nil].
• Don’t forget that instance variables are referred to as @bar within getters and setters, as Section 3.4 of ELLS explains.
• Although the existing attr_accessor can handle multiple arguments (e.g. attr_accessor :foo, :bar), your version just needs to handle a single argument.
• Your implementation should be genreal enough to work in the context of any class and for attributes of any (legal) variable name