Module 1 · What testing actually is Lesson 1 of 15
A bug report a developer can act on
A defect report is a message to somebody who cannot see your screen: steps, expected result, actual result, environment, evidence. Missing any one of those five costs a round trip.
The concept
A bug report is a short document that lets somebody who was not there reproduce the problem. Title, environment, steps, expected, actual, and the evidence — a screenshot, a log line or a screen recording. Six lines, and a developer can act without asking you a single question.
The title carries the finding: "Applying to a closed job saves the application and shows a success message" tells the developer where to look. Number the steps so they can be repeated exactly, and say which browser, device and build — "not working on my phone" is not a report.
Title: Login fails with a VALID password on iPhone Safari
Build: web 1.4.2 . iPhone 13 . Safari 17
Steps:
1. Open /login
2. Enter a@b.com / correct-password
3. Tap "Sign in"
Expected: lands on the dashboard
Actual: shows "Invalid credentials"; the account was created today
Attach: screenshot + the console error
Reproducible? Yes, 3 of 3 times. That single line is what gets it fixed.Common mistakes
The mistake is "login not working", which forces a round trip of questions and makes the report look careless. The second is combining three unrelated problems in one report, so two get fixed and the third is quietly closed with them. One finding per report.
Worked example
"Login is broken" is not a report. "On Chrome 120, submitting the login form with a valid new user shows the dashboard and then returns to login after two seconds — expected: stays on dashboard. Recording attached" is a report, and the recorder is how you got the two seconds.
Your practice task
Write five bug reports from a website you use daily, each in the five-part format, and rank them by severity.
Do this before moving on. Reading a solution teaches the shape of it; typing it teaches you.
Key takeaway
A bug report is a short document that lets somebody who was not there reproduce the problem.
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Finish every lesson to unlock the certificate. Each one ends in a practice task — do them and the final project brief writes itself.