Independent testing is testing done by someone other than the person who built the software, to get a view free of the builder's assumptions. Independence can come from a separate team, or from a tester's independent mindset within the same team.
Why it matters: People are blind to their own mistakes, so an outside view finds problems the builder can't. But separate test teams slow feedback and create silos, so how independence is achieved matters as much as having it.
In practice: Many teams now embed testers with developers and treat independence as a mindset, not a reporting line. Testers question assumptions, represent users and stay alert to their own biases, while still working closely with the team.
Examples:
- A tester embedded in a development team who still questions the team's assumptions.
- An organisation moving away from a separate test department while keeping testers' independent perspective.
Common pitfalls:
- Equating independence with distance, and losing rapid feedback.
- Assuming testers are immune to the same biases as developers.
Should developers test their own code? Yes, developers can and should test their own code. But that isn't all the testing needed. An independent perspective still finds problems the builder misses.
