Fixing AfterAll TypeError: Failed to execute 'appendChild' on 'Node': parameter 1 is not of type 'Node'
This error occurs when passing an object instead of a string to Jasmine's describe():
# Bad
describe(HoverClass, function() { ... })
# Correct
describe('HoverClass', function() { ... })
Related cards:
How to view Image Metadata on the Linux Command Line with ImageMagick
ImageMagick has a command line tool called identify which can read image metadata:
>identify -verbose DSC00136.JPG
Image: DSC00136.JPG
Format: JPEG (Joint Photographic Experts Group JFIF format)
Class: DirectClass
Geometry: 5472x3648+...
Fix external Displays switching not on when plugging notebook in docking station
If your external displays not switching on or showing a weird behavior (for e.g. all displays getting the same configuration all the time) you can fix it by switching off all external displays and re-enabling only one in the first step. Afterwards...
How to create memory leaks in jQuery
jQuery doesn't store information about event listeners and data values with the element itself. This information is instead stored in a global, internal jQuery cache object. Every time you add an event listener or data value to a jQuery object, ...
DNS debug tools
There are several tools for DNS debugging which offer you more or less information. Most of the time the more simple ones, like host oder nslookup will be sufficient.
host
simple DNS lookup utility.
>host heise.de
heise.de has addr...
Video transcoding: Web and native playback overview (April 2020)
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 ...
How to make Rational#to_s return strings without denominator 1 again
The way Rational#to_s works on Ruby has changed from Ruby 1.9 on. Here is how to get the old behavior back.
You may want this for things where Rationals are being used, like when subtracting Date objects from one another.
What's happening?...
JavaScript without jQuery (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, and we can polyfill the missing pieces
- Un...
Fixing flaky E2E tests
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 ...
List of handy Ruby scripts to transcode different file types (often by using GPT)
It's 2024 and we have tools like ffmpeg, imagemagick and GPT readily available. With them, it's easy to convert texts, images, audio and video clips into each other.
For the everyday use without any parameter tweaking I'm using a collection of ti...
Lightning Talk: Coverage based Test Case Prioritization in Ruby on Rails
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....