History & Inspection

A repository's history is the most underused testing artifact in your company. This module teaches you to read it — and to turn "what changed?" from a question you ask into a question you answer.

Why This Module Matters

Picture a normal Monday. A build lands on your environment with the note "bugfixes and improvements". You have four hours and two hundred test cases. Which ones do you run?

A tester who can't read a repository guesses, or runs everything and finishes nothing. A tester who can read a repository opens the log, sees that the last twelve commits touched the checkout flow and the currency formatter, and tests those — deliberately, with evidence, and with a defensible answer when someone asks why.

That is the real skill in this module. git log and git diff are just the two commands that unlock it.

What You'll Learn

• How to read a project's history with git log, and why git log --oneline is the version you'll actually live in
• How to filter history down to what matters: recent commits, a single file, a single author
• The difference between git diff and git diff --staged, and why beginners constantly see "nothing" from the first one
• How to read a diff hunk: what the + and - lines really mean
• How to turn a change set into a focused, risk-based test scope before you open a single test case

Pro Tip

A diff tells you what changed. It does not tell you what broke. Use it to aim your testing, never to replace it — the bug you're hunting is often in the code that wasn't touched but depended on the code that was.