pragmatic ruby xml computing scripting languages ruby (programming language) ruby programming language c# extreme programming junit software engineering software testing test test driven testing computer programmers software development unit testing the pragmatic programmer andy hunt (author) dave thomas (programmer) java nunit cvs computer programming concurrent versions system agile physics scrum mechanics materials science plasticity stress (mechanics) tensors test-driven development javascript curly bracket programming languages variable (programming) this (computer science) smalltalk web application framework