Toy Robot

What is this ?

Toy Robot is a ruby coding exercise that we get our potential candidates to complete for us (Mable) to understand their capabilities.

What do I need to do ?

Specification

Description

The application is a simulation of a toy robot moving on a square tabletop, of dimensions 5 units x 5 units.
There are no other obstructions on the table surface.
The robot is free to roam around the surface of the table, but must be prevented from falling to destruction. Any movement that would result in the robot falling from the table must be prevented, however further valid movement commands must still be allowed.
Create an application that can read in commands of the following form:

PLACE X,Y,F
MOVE
LEFT
RIGHT
REPORT

PLACE will put the toy robot on the table in position X,Y and facing NORTH, SOUTH, EAST or WEST.
The origin (0,0) can be considered to be the SOUTH WEST most corner.
The first valid command to the robot is a PLACE command, after that, any sequence of commands may be issued, in any order, including another PLACE command. The application should discard all commands in the sequence until a valid PLACE command has been executed.
MOVE will move the toy robot one unit forward in the direction it is currently facing.
LEFT and RIGHT will rotate the robot 90 degrees in the specified direction without changing the position of the robot.
REPORT will announce the X,Y and F of the robot. This can be in any form, but standard output is sufficient.
A robot that is not on the table can choose the ignore the MOVE, LEFT, RIGHT and REPORT commands.
Input can be from a file, or from standard input, as the developer chooses.
Provide test data to exercise the application.

Constraints

The toy robot must not fall off the table during movement. This also includes the initial placement of the toy robot. Any move that would cause the robot to fall must be ignored.

Example Input and Output

PLACE 0,0,NORTH
MOVE
REPORT

Output: 0,1,NORTH

PLACE 0,0,NORTH
LEFT
REPORT

Output: 0,0,WEST

PLACE 1,2,EAST
MOVE
MOVE
LEFT
MOVE
REPORT

Output: 3,3,NORTH

Why am I doing this ?

At Mable we believe these kind of coding challenges will give us more visibility on the candidate's strengths. On the other hand, candidates can show their capabilities by applying what they already know.

What’s next ?

clone this repo
Do your changes
Email us the link to your public git repo with the solution

What do We expect as deliveries?

While we love to see a working code, the most important aspects we are looking into are:

How you would approach a problem
How you approach around testing
Any other related documents (E.g README) that will help someone to set up and run this project.

What are the next steps ?

Once you completed the exercise and let us know, we'll go through your code and if we are happy with your code, we'll contact you for the next step, which is a discussion on this code and your thinking / approach to this problem.

Toy robot is a very common coding test and I can find heaps of sample code ?

Yes, true, this is a very famous common test. However, we sincerely hope that you'll not just copy and paste a code from internet :).

In Fact the author of this test himself has described, why this test is still relevant, even though there are many examples out there

Toy Robot Coding Puzzle

All the very best!!!

Run this

Install this

Git clone this repo into the folder of your choice, then cd to it
install Ruby 2.7.3 using the version manager of your choice (I'm partial to rbenv, but you can use what you like). rbenv install 2.7.3, rbenv local 2.7.3.
Install Rubygems if you haven't already. It's a per-OS thing, so you may need to look up your OS's install instructions. I like MacOS (with Homebrew): brew install rubygems
Install Bundler: gem install bundler
Install this repo's gems: bundle install. We're using only test-unit, so it's just that and nothing else.

Test this

ruby test/robot_test.rb. Done.

tyrant/toy-robot