While upgrading CarrierWave from version 0.11.x to 3.x, we encountered some very nasty fails. Below are the basic changes you need to perform and some behavior you may eventually run into when upgrading your application. This aims to save you some...

Localizing a non-trivial application can be a huge undertaking. This card will give you an overview over the many components that are affected.

When you are asked to give an estimate for the effort involved, go through the list below and check wh...

Web applications can be used by multiple users at the same time. A typical application server like Passenger has multiple worker processes for a single app. In a distributed deployment setup like we use at makandra you w...

For my computer science bachelor's thesis I programmed and evaluated a CLI Test Case Prioritization (TCP) tool for makandra. It has been written as a Ruby Gem and was tested and evaluated against one Ruby on Rails project....

Slides for Henning's talk on Sep 21st 2017.

Understanding sync vs. async control flow

Talking to synchronous (or "blocking") API

print('script start')
html = get('/foo')
print(html)
print('script end'...

Intro

Embedding videos on a website is very easy, add a <video> tag to your source code and it just works. Most of the time.

The thing is: Both the **operating system and Browser of your client must support the container ...

An end-to-end test (E2E test) is a script that remote-controls a web browser with tools like Selenium WebDriver. This card shows basic techniques for fixing a flaky E2E test suite that sometimes passes and sometimes fails.

Although many examples ...

This is a presentation from 2019-01-21.

Summary

• We want to move away from jQuery in future projects
• Motivations are performance, bundle size and general trends for the web platform.
• The native DOM API is much nicer than it used to be, a...

A flaky test is a test that is often green, but sometimes red. It may only fail on some PCs, or only when the entire test suite is run.

There are many causes for flaky...

In Ruby (almost) everything is an Object. While this enables a lot of powerful features, this concept might be confusing for developers who have been programming in more static languages, such as Java or C#. This card should help understanding t...