Block implementation

Goal

Your task is to complete the implementation of the Block class (block.rb) so that the specs (block_spec.rb) run green.

Block provides an abstraction for performing boolean operations on a numerical range. It is used for calculating the interaction of free and busy time periods on a schedule.

A Block is a Value Object which has a starting value (called top or start) and an ending value (called bottom or end). These properties are numeric values which could represent points in time, or an arbitrary numeric scale.

Blocks can be combined and subtracted from one another to yield other blocks or arrays of blocks depending on whether the original blocks are contiguous or not.

For example:

  # Addition of overlapping ranges:
  Block.new(3, 8) + Block.new(5, 12) == Block.new(3, 12)

  # Subtraction of one block from the middle of another:
  Block.new(5, 25) - Block.new(10, 20) == [Block.new(5, 10), Block.new(20, 25)]

The specs are provided, but the implementation is incomplete. Implement the remaining methods on Block so that all the tests pass. Try to make your solution as elegant and readable as possible.

Good luck!

Installation

bundle install
rspec spec

Instructions

1. Check out a new branch to do your work.
2. Run rspec spec/block_spec.rb to view the specs for the Block class.
3. Fill in the missing method implementations for the Block class to make all the specs run green. Do not change the spec files.
4. Try to refactor your solution to remove any obvious code smells. Don't worry about making it perfect. First make your code correct, and then refactor to the extent necessary that your solution is clear and maintainable. Manage your time wisely and stop when its good enough.
5. Please commit your changes to your working branch frequently so I can get a sense of your development process.
6. Your solution would be rejected if it does not have frequent commits. The commit messages should be brief and self-explanatory.

Hints

1. You will find it helpful to make use of the existing query methods that have already been implemented for you.

Assessment

I will evaluate your solution based on:

1. Correctness (does it satisfy the test cases?)
2. Elegance (is the solution clean, clear and well factored?)
3. Process (did you take a systematic approach to solving the problem?)