Movie Store Interview Question

This interview question is taken from a real interview which I ran for several years and continues to be used in a number of institutions.

The interview was conducted as a TDD, pair-programming challenge. This is important to note. It was not the eventual solution that mattered so much as the journey there. Sometimes we would hire people who didn’t get the solution, and other times we wouldn’t hire people who did.

The Challenge

Implement a “movie store” (like blockbusters or Netflix). The store needs to hold a number of movies (let’s say a maximum of 100, but for our testing purposes 4 or 5 is sufficient). We need to be able to search the movie store for titles based on a number of different criteria.

Sounds pretty simple huh?

It’s amazing how many people it trips up though.

In the interview we would reveal each requirement one by one. As we’re doing TDD we’re building the requirements one at a time. Just like in the interview, I'll reveal each requirement one at a time.

The goals

The solution should have beautiful, clean code, without repetition or hacks. It should be code that you would be proud to have in production.

It should be well tested.

You do not need to worry about databases, threading, user interfaces, API access or 3rd party libraries. This a pure Java question.

You should be mindful about performance, but it’s not a major concern.

You should not over engineer the solution.

The solution

Don’t worry if you’ve never done TDD- I even teach you how to do TDD from the start.

This course is approximately an hour long and comes with all the code available to download.

The training is about much more than just coming up with a solution- we discuss many of the areas that candidates fall down in interview and how to avoid them.