In unit tests you might run in problems, when your code uses PHP built-in functions, that emit certain hard-coded values like session_start(). When you use PHP namespaces, however, you can solve this problem in an elegant way.
This rule takes an SVG file as input and returns two PNGs. One is rendered with 72 dpi, which maps 1 SVG pixel to one output pixel. The other, firstname.lastname@example.org, is rendered with twice the solution to fit for Retina displays.
If you use RequireJS and jQuery in a project, you might find yourself in a situation, where you embed jQuery before RequireJS, but still need to have the “jquery” dependency respected. This article describes, how to achieve this.