Brief¶ ↑

A simulation of a toy robot moving on a square tabletop. Programming exercise for REA job application.

Running demo at: floating-cove-6107.herokuapp.com

Requirements¶ ↑

• 5x5 table

• No obstructions

• Any movement resulting in the robot falling off the table are to be ignored. Further input accepted.

• Commands: PLACE, MOVE, LEFT, RIGHT, REPORT

  • PLACE(X, Y, FACING) places the robot on the table facing the direction input

  • MOVE the robot 1 space forward

  • LEFT rotate the robot 90 degrees

  • RIGHT rototate the robot 90 degrees

  • REPORT announces the X, Y and direction the robot is facing

• Origin position 0,0 the Southwest corner

• Robot must be placed on the table

• Ignore all commands until a valid PLACE command

• Robot can be re-placed on the table

• Input source developer’s choice (standard input, file etc.)

• Graphical representation not required

Features¶ ↑

• Web application!

  • Thread-safe (i.e. each session has it’s own state)

  • Actions call friendly URLs via AJAX

  • Deployed to the cloud (Heroku)

  • REA visuals

  • Chaos Robot! (similar to Chaos Monkey, randomly performs 10 actions)

• Supports variable table dimensions

• Full code comments, rdoc, static methods, removed unused autogenerated code

• Skeleton for ability to add many robots to a table

  • Table aware of Robot(s)

  • Actions have placeholders for Robot IDs to diferentiate

• For demonstration purposes only, monkey patched Array core class to demonstrate novel approach for rotation (LinkedList-type functionality instead of an easy switch statement)

  • Also patched the JavaScript Array object!

Development¶ ↑

• Read up on Minitest v RSpec, decided to choose Minitest DSL with standard matchers/mocks for simplicity

  • Easy enough to leverage Mocha, Shoulda etc.

  • TDD unit & integration tests

  • One assertion per test

  • No parenthesis for cleaner readability

• Input ignores case

Possible Improvements¶ ↑

• Multiple robots on the table at once (although basic foundations of ID are in place)

• Functional tests on the ad-hoc web components (view, thin controller)

• Proper Javascript (module pattern, tests)

Resources¶ ↑

• blog.arvidandersson.se/2012/03/28/minimalicous-testing-in-ruby-1-9 (Minitest introduction, Spec-only)

• ruby.awsblog.com/post/TxUMU0234OS1Q3/From-RSpec-to-Minitest (pro Minitest, Spec-only)

• brandonhilkert.com/blog/7-reasons-why-im-sticking-with-minitest-and-fixtures-in-rails/ (pro Minitest and Fixtures)

• code.tutsplus.com/tutorials/ruby-for-newbies-testing-with-rspec–net-21297 (simple RSpec guide)

• www.agileventures.org/articles/testing-with-rspec-stubs-mocks-factories-what-to-choose (Mocks)

• www.mattsears.com/articles/2011/12/10/minitest-quick-reference (Minitest cheat sheet)

• regex101.com/ (regular expression tester)