Coding exercises for Bueno

Description

Coding exercise as per requested by the Bueno. The Mars Rover programming exercise.

Tested using java 8.

Usage

This will run the rover application

$ java -classpath classes com.pyuser.bueno.App

Assumptions :

• No 3rd party libs, save for jUnit.
• Invalid commands does increment the command count.
• Grouped commands are not atomic, as in all commands will be attemped even if one of the commands in the group does not succeed. Though I can see why this would not be a good idea, I can change this behaviour reasonably easily, by not swallowing the exception in the group commands loop.
• There is no undo facility (see possible improvements).

Design

• Rover needs to be instantiated with a plateau. No plateau, no rover.

Possible improvements

• Each of the commands could be made into a class viz the GOF Command pattern. This will provide an ability to easily add new commands as well as to implement add undo functionality.
• Have the exceptions have a mnemonic value, so as to be able to easily distinguish from other types of exceptions, as opposed to having a class per type of exception.
• Plateau coordinates are (x, y). Arrays are (rows, cols) which is (y, x) or vice versa. I had a lot of trouble with grokking this.

Feeback received

We've just finished our code reviews, and unfortunately you weren't selected for interview. The feedback from our developers was as follows:

Pros

• README very well written

Cons

• No need to catch the exceptions in the test cases
• Limited/no use of proper visibility accessors
• We ask not to use external libraries - I don't see the point of rewriting Pair when you can simply introduce a class called Position
• Extraneous links to external references. Not that I don't see the benefits per se, when they are useful
• Tests are too big/complex and hard to read
• boolean res = false; [...] res = true; return res;
• IIRC reference comparison == with Integers works only with small numbers, and only with certain VMs (OpenJ9 does not work with this at all)
• The solution lacks OO design
• In general not super clean - I don't think an IDE like IntelliJ (which has warnings/suggestions built-in) was used
• ; //we swallow and then throws Exception in the signature
• Why _env?