Sergio Sastre Flórez

Sergio Sastre Flórez

appDev GmbH & Co. KG, Lead Android Developer

Munich, Germany

Google Developer Expert for Android with 10+ years of experience, currently consulting for Deutsche Bahn Systel, having worked for other prominent companies such as Check24, Liferando, AutoScout24, and Hermes Germany.

He is a passionate advocate for software testing and has authored numerous blog posts on the matter.

He has also authored open-source libraries & repos on Android UI testing (e.g. AndroidUiTestingUtils & Android Screenshot Testing Playground) as well as contributed to others like KasperskyLab/Kaspresso.

When not coding, he enjoys playing sports like football, running, rollerblading or snowboarding in the mountains.

loves challenges and making things happen.

Area of Expertise

  • Information & Communications Technology


  • Testing
  • Android
  • UI Design

Screenshot Testing for Android: Which Library is Right for You?

In recent years, screenshot testing has become an increasingly popular way to automate UI testing in Android applications, with new libraries emerging regularly. That makes hard to determine which one is the best fit for your project.

In this tech-talk, we'll explore the top screenshot testing libraries, from on-device to JVM-based libraries, including the newest player in the game: Roborazzi, based on Google's Robolectric.

We'll dive deep into each library's unique features and compare their pros and cons to help you make an informed decision about which one is right for your project.

Whether you're new to screenshot testing or have experience with it, this tech-talk will take your UI testing skills to the next level. You'll leave this talk with the knowledge to confidently choose the best screenshot testing library for your projects. Don't miss out on this opportunity to become a screenshot testing Ninja in Android!

Mastering Screenshot Testing Libraries for Android: A Hands-On Workshop

Join me for an in-depth workshop where you'll discover the most popular screenshot testing libraries for Android. With so many options to choose from, I'll guide you through the pros and cons of each library, including the newest player on the scene: Roborazzi, based on Robolectric from Google.

This is a hands-on workshop where you'll have the opportunity to explore the different libraries and write both, JVM and on-device screenshot tests on your own. By the end of the workshop, you'll have the skills and knowledge to confidently choose the best screenshot testing libraries for your projects.

Regardless of your level, this is a must-attend workshop to take your UI testing skills to the next level. Don't miss out on this chance to become a screenshot testing pro!

Android at Scale

This panel will take a look at how Android teams scale at different companies. Let’s examine some the ways teams conduct code reviews, do onboarding, continuous integration and more. How do some teams deal with issues like tech debt, refactor vs rewrite, etc. The panelists will share best practices and experiences from their current teams and past employers.

Writing bulletproof code with property-based testing

Unit tests are an important part of the development process. Among other things, they help us verify the correctness of our code.

Thus, when writing tests, we usually pick one or two relevant examples, let the tests run green and call it a day. This is called example-based testing.

But, is that enough? Have you missed any significant case? Have you considered all edge-cases? What if any of those non-tested examples would make the app crash?

Fear not, we can fill that gap with property-based tests. Let me show to you how, step by step.

In this tech-talk you will learn:
- some easy tips to improve your unit tests
- why example-based unit tests are not always enough
- how property-based testing can make your tests more robust
- property-based testing in very detail:
* what it is
* its pros and cons
* which tools/frameworks are available for implementing them
* how to make the most out of them

And all that by using as examples some features you would find in most Android apps, like "create account" or "text editing.

An Introduction to Effective Snapshot Testing on Android

UI tests are a powerful tool to detect regression bugs. However, they are tedious to write and run very slow. But they are not the only tool we got to test the UI:
snapshot tests are some specific type of UI tests, that are not only easier to write but also run much faster than standard UI tests. They even help detect visual regression bugs that Espresso/UiAutomator tests cannot. Indeed, they are more widely used than UI tests by big companies such as Airbnb, with ≈ 30.000 snapshot tests, and Uber, with thousand of snapshot tests vs. a handful of UI tests, among others.

While there are plenty of resources about writing UI tests on Android, the same doesn't exist for snapshot tests. There is no guidance.

So, what is actually snapshot testing? how do you write a valuable snapshot test? what are the best practices? what are the pitfalls you have to take into account?

If you want to know how to get the most out of snapshot testing, come and join this tech talk. You will learn:
- what is snapshot testing and how your app can benefit from it
- how to decide what to snapshot test
- how to write your first meaningful snapshot test
- tips and tricks for better snapshot testing and what pitfalls to avoid

Sergio Sastre Flórez

appDev GmbH & Co. KG, Lead Android Developer

Munich, Germany

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