Intro to the Spock testing framework && Co/contravariance

This is a past event

45 people went

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19:00 - 20:00
Live coding session: Intro to the Spock testing framework

Speaker: Bianca Leuca (, software developer @ Mozaic Labs

Spock is a testing framework for Groovy and Java applications. The aim of this talk is to give you a practical demonstration of Spock's features that help you write expressive tests, and speed up the coding process. Bianca will perform a live coding session using Spock. She will be using Groovy, but fear not! If you are a little bit familiar with Java, you will see that you can easily read the code.

20:00 - 21:00
Talk: Covariance and contravariance in Java

Speaker: Alin Pandichi (, software developer @ Mozaic Labs

Short abstract:

Make sense of how the concepts of covariance and contravariance are used in typed programming languages.

While merrily browsing the Internet and reading technical articles about programming, you may encounter the terms of "covariance" and "contravariance." These sound spooky enough to make you consider closing the tab and forgetting all about it, as if it were a bad dream. It doesn't have to be that way!

These two terms are actually abstract mathematical concepts that are (mis)used in computer science. During this talk, we'll try to make sense of these things, together. We'll lightly touch upon what covariance and contravariance means in a mathematical scenario (Don't worry, we won't be talking about functors!). Then, we'll see how these concepts are used to describe subtyping relationships in the Java programming language. There will be code examples, of course!