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...

While it might seem trivial to implement an invoice that sums up items and shows net, gross and vat totals, it actually involves a lot of rules and caveats. It is very easy to create invoices where numbers don't add up and a few cents are missing....

The way MySQL's FULLTEXT tokenizer splits text into word tokens might not always be what you need. E.g. it splits a word at period characters.

Since the tokenizer has near-zero configuration options (minimum word length and stopwords list), you n...

When you are trying to install/update VirtualBox Guest Additions on your guest machine but the setup is for a different/older version (for example 4.0.4 tools for a 4.1.x VirtualBox installation), try this:

sudo apt-get install virtualbox-gue...

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 ...

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?...

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....

You are getting when connecting via SSH or deploying with Capistrano (which uses SSH):

Too many authentication failures for username

This is caused by having too many SSH keys added to your keyring or ssh-agent. Your ssh-agent will throw all...

If you have an html_safe string, you won't be able to call gsub with a block and match reference variables like $1. They will be nil inside the block where you define replacements ([as you already know](https://makandracards.com/makandra/2...

Many of our developers love to use the "awesome" window manager on Linux. However, RubyMine dialogs occasionally defocus while typing.

Here is a fix for that, tested on awesome 3.4, 3.5 and 4.0 (Ubuntu 14.04 and 16.04).

Problem

Consider the...