Code Challenge “Vrolijke Framboos” Postmortem

Tuesday we had our second ever “Vrolijke Framboos” (Dutch for Happy Raspberry)
Java code challenge at JDriven and it was a blast! This year’s
challenge was to create a REST service client that would play a number guessing
game with the server. After setting up a session you would guess a number and the
server would respond with either “lower”, “higher” or “bingo”. The goal was to guess
as many numbers in the two minutes you’d be given. Given the name of the challenge
you can probably guess that the target platform would be a
Raspberry Pi!

It was an incredible and fun experience and in this post I want to explain how I
approached the challenge and how my solution ended up in the second place, making
me just miss the opportunity to take home the trophy and a new Raspberry.

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Joy of Coding… and mutation testing in Java

For many years now it has been good practice to write unit tests for your source-code.
And also to use test coverage reporting to see how much of your code is covered by tests.
Although line + branch coverage reporting is quite useful, it doesn’t tell you how good your unit tests actually are. Hence it’s even possibly to achieve 100% coverage without even a single assert in your tests.

Being interested in better ways of testing I attended the “Mutation testing” workshop during this years Joy of Coding conference.
Mutation testing is a radical different approach of executing and analyzing the result and coverage of your unit tests. Instead of measuring how much of your code is “accessed from” your unit tests it determines how much of your code is actually “tested by” your unit tests.

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