Smoke & Sanity Testing
Part of the QA Testing Roadmap
In short
Before spending a day testing a new build, spend ten minutes checking it isn't completely broken. That's smoke testing, and its narrow cousin is sanity testing.
Smoke testing checks that the most critical functions work at all after a new build (a very shallow, broad check); sanity testing verifies a specific fix or feature works after a small change — both are quick, focused checks.
Think of it like this
The electrician's quick check
After wiring a new flat, the electrician flips every main switch to see lights, fans and plugs come alive. That's smoke. Later he fixes one fan regulator and checks just that fan and its switchboard. That's sanity.
Watch it happen
Smoke vs sanity
Smoke
- Wide and shallow
- Runs on every new build
- Can login, search, checkout start?
Sanity
- Narrow and focused
- After a small fix or change
- Is the coupon bug really fixed?
Smoke asks 'is this build testable at all?' Sanity asks 'does this one change make sense?' Both are quick.
The big ideas
What you need to know
Minutes, not hours
A smoke suite usually runs in minutes. If it fails, the build goes back before anyone wastes time.
Smoke is often automated
Many teams run smoke tests automatically after every deploy to the test or production server.
Sanity is often manual
A quick targeted check on the changed area, sometimes without formal test cases.
Save yourself the pain
Common mistakes
Oops
Starting full testing on a build where login is broken.
Do this instead
Run smoke first. If critical paths fail, reject the build and save everyone a wasted day.
Oops
Treating sanity testing as full regression.
Do this instead
Sanity only checks the changed area makes sense. Regression is the broad safety net.
Your mission
Write a smoke suite
Quick check
A developer fixes a bug where the 'Forgot password' email wasn't sent. You quickly check that flow and its nearby screens. What is this?
Go deeper
- 1Draft a smoke test checklist covering the 5-6 most critical functions of a hypothetical app.
- 2Learn why a failed smoke test should block further testing until fixed.
- 3Understand the difference between smoke testing's breadth and sanity testing's narrow focus.
More topics at this stop
Types of Testing (Functional, Non-Functional)
Black Box vs White Box vs Gray Box Testing
Test Case Design Techniques
Equivalence Partitioning & Boundary Value Analysis
Test Case Writing
Exploratory Testing
Regression Testing
Test Data Preparation
Bug Life Cycle
Writing Effective Bug Reports
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