What?! Pre-interview code challenge?!

It doesn't matter how many years of experience you have, how many coding challenges you've solved in your spare time or how many open source contributions you've made, companies still want you to complete their tests or coding challenges. We can debate it but there's very little we can do about it.

But then I bumped into a new beast - pre-interview tests. You write a coding challenge in order to secure an interview. In other words, don't bother to send in you resume unless you spend several hours writing a program. And as in this instance (I'm not going to disclose the company's name) they ask you to make it public on github. Great idea ... if you want to analyze other people's approach :-) And that's what I did.

After analyzing several repositories I found a few patterns. Their common denominator is:

People don't really read requirements.

And here's why.

• The code should be written in Java but you can see people trying to outsmart by providing Python, Go or Haskell version. It may be fine as a supplemental implementation to impress the recruiter but not on its own.
• None of the implementations I could check came with any tests at all! Unit, integration, anything. That's a very bad sign. Although I personally don't advocate TDD I still think that tests are important, especially when it comes to coding some system logic. They also speed up the development cycle as you don't need to build and run your application just to check it the code works.
• Although people were asked to structure their application as if it was a production grade application some still put everything in one class.
• Missing documentation. At least javadoc, better yet stand alone handcrafted document outlining how the application works.
• Build instructions. People rarely bother to write quick instructions about how to build the application. Although it may be clear that gradle/maven has been used it's still nice to provide this in writing.
• Some assume that a CSV document can be created with simple List.join(",").
• Some even assume that parsing JSON means splitting a string by ,.
• People ignore application return values. They just spit out an error message and bail out (so the return value is 0 indicating successful completion).

Advice to people applying to those companies. It's unlikely you're the first one applying. Search github, bitbucket, gitlab and the likes. That can give you an idea about your competition. It could also help you out with your code should you get stuck.

And a closing message to companies trying to make it easier for them by asking people to write code before applying. Asking people to code first, massively limits the pool of people applying. There are thousands of great developers who don't want to spend hours coding just to wait if you come back to them. I'd also say that it attracts wrong kind of people.

1. people who like to solve challenges and have time to do that but are not really into a long term relationship
2. people with little experience hoping to skip the line
3. cheaters who smell a chance of landing a job

I still think it is much better and efficient to do a quick screening (via skype or the likes) and ask a candidate to join you for a day (preferably pay the person for working with you that day).