# Secure Software & Testing · 1

[Agila University track](https://edu.agilaos.com/track.php?track=28&lang=en)

About 15 minutes per lesson. Predict, run, change, explain, then complete the check in University.

- [Lesson 1: Validate before crossing a boundary](lesson-1/lesson.html)
- [Lesson 2: Separate data from instructions](lesson-2/lesson.html)
- [Lesson 3: Regression tests must challenge the fix](lesson-3/lesson.html)