Smoke Testing

Overview

Smoke Testing performs quick, automated checks of critical functionality to verify the application works at a basic level. It provides rapid feedback that the system is functioning before running more comprehensive tests.

⚡ Fast Validation

Smoke Testing ensures:

• Application starts without crashing

• Critical paths work

• Core features functional

• Basic integration operational

• Quick detection of obvious issues

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When to Use Smoke Testing

✅ Good Use Cases

Scenario	Why Smoke Test
Post-deployment	Verify deployment successful
Every commit	Quick feedback loop
Before full regression	Fail fast before expensive tests
Health monitoring	Continuous system checks
Quick build validation	CI/CD gate
Release validation	Pre-release sanity check

❌ Anti-Patterns (Don't Do)

• ❌ As only testing (need comprehensive tests)

• ❌ Testing non-critical features

• ❌ Slow smoke tests (defeats purpose)

• ❌ Smoke tests that are flaky

• ❌ No monitoring of smoke test results

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Smoke Test Characteristics

Speed: 5-15 minutes

Must complete quickly
↓
Get rapid feedback
↓
Fast failure detection

Target: <15 min for full suite
Typical: 5-10 minutes
Too slow: >20 minutes (reconsider)

Coverage: 20-30% of features

Critical paths only:
✓ Login/authentication
✓ Core business function
✓ Payment processing (if applicable)
✓ Critical integrations
✓ Logout/session

Not tested:
✗ Edge cases
✗ Advanced features
✗ Rare scenarios
✗ Nice-to-have features

Simplicity: Happy path only

Test the common case:
✓ Valid input
✓ Success scenario
✓ Normal operation

Not tested:
✗ Error cases
✗ Edge cases
✗ Invalid inputs
✗ Failure scenarios

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Practical Examples

Example 1: Web Application Smoke Test

Workflow: Quick smoke test for web app

Purpose: Verify application is running

Duration: 8 minutes

Test 1: Application Loads (1 min)
  [Navigate to home page]
  [Wait for page load]
  
  Verify:
  ✓ Page loads without error
  ✓ No 500 error
  ✓ Page title correct
  ✓ Main content visible
  
  If fails: 🔴 STOP - application broken

Test 2: User Authentication (2 min)
  [Navigate to login page]
  [Enter valid credentials]
  [Click login button]
  
  Verify:
  ✓ Login succeeds
  ✓ Redirects to dashboard
  ✓ User name displayed
  ✓ No error messages
  
  If fails: 🔴 STOP - authentication broken

Test 3: Core Functionality (2 min)
  [Access main feature]
  [Perform basic operation]
  [Check result]
  
  Verify:
  ✓ Feature accessible
  ✓ Operation completes
  ✓ Result shown
  ✓ No errors
  
  If fails: 🔴 STOP - core feature broken

Test 4: Data Retrieval (2 min)
  [Navigate to data view]
  [Load data]
  
  Verify:
  ✓ Data loads
  ✓ Displayed correctly
  ✓ No loading errors
  
  If fails: 🔴 STOP - database connection down

Test 5: Logout (1 min)
  [Click logout]
  
  Verify:
  ✓ Logout succeeds
  ✓ Redirects to login
  ✓ Session cleared
  
  If fails: ⚠️ WARNING - logout issue

Results: ✅ Application functional (pass all critical checks)

Example 2: Mobile App Smoke Test

Workflow: Smoke test for mobile application

Purpose: Verify app core functionality

Duration: 10 minutes

Test 1: App Launches (1 min)
  [Launch application]
  [Wait for startup]
  
  Verify:
  ✓ App starts without crash
  ✓ Splash screen appears
  ✓ Main screen loads
  
  If fails: 🔴 STOP - app won't start

Test 2: Authentication (2 min)
  [Enter credentials]
  [Tap login]
  
  Verify:
  ✓ Login succeeds
  ✓ Home screen displayed
  ✓ No authentication errors
  
  If fails: 🔴 STOP - can't login

Test 3: Core Feature (2 min)
  [Tap main feature]
  [Perform action]
  
  Verify:
  ✓ Feature responds
  ✓ Action completes
  ✓ Results visible
  
  If fails: 🔴 STOP - feature broken

Test 4: Data Sync (2 min)
  [Trigger data refresh]
  [Wait for sync]
  
  Verify:
  ✓ Sync completes
  ✓ New data displayed
  ✓ No sync errors
  
  If fails: 🔴 STOP - data connection down

Test 5: Navigation (2 min)
  [Tap menu items]
  [Navigate screens]
  
  Verify:
  ✓ Screens load
  ✓ Navigation works
  ✓ No crashes
  
  If fails: ⚠️ WARNING - navigation issue

Test 6: Logout (1 min)
  [Tap logout]
  
  Verify:
  ✓ Logout succeeds
  ✓ Return to login
  
  Results: ✅ Mobile app functional

Example 3: API Service Smoke Test

Workflow: Smoke test for API service

Purpose: Verify API responding correctly

Duration: 5 minutes

Test 1: Service Health Check
  [GET /health]
  
  Verify:
  ✓ Status: 200
  ✓ Response: {"status": "healthy"}
  ✓ Response time: <100ms
  
  If fails: 🔴 STOP - service down

Test 2: Authentication Endpoint
  [POST /auth/login]
  [Credentials: valid]
  
  Verify:
  ✓ Status: 200
  ✓ Returns: {token, expires}
  ✓ Token valid format
  
  If fails: 🔴 STOP - can't authenticate

Test 3: Core API Endpoint
  [GET /api/data]
  [Headers: Bearer token]
  
  Verify:
  ✓ Status: 200
  ✓ Returns: [data array]
  ✓ Data not empty
  
  If fails: 🔴 STOP - API not responding

Test 4: Database Connectivity
  [GET /api/data?id=1]
  
  Verify:
  ✓ Status: 200
  ✓ Returns: single record
  ✓ Record has expected fields
  
  If fails: 🔴 STOP - database down

Test 5: Error Handling
  [GET /api/data?id=invalid]
  
  Verify:
  ✓ Status: 400
  ✓ Returns: error message
  ✓ No 500 error
  
  Results: ✅ API service operational

Example 4: E-Commerce Smoke Test

Workflow: E-commerce platform smoke test

Purpose: Quick validation of shopping flow

Duration: 12 minutes

Test 1: Site Loads (1 min)
  [Navigate to homepage]
  
  Verify:
  ✓ Page loads
  ✓ Products visible
  ✓ No errors
  
Test 2: User Login (2 min)
  [Login with test account]
  
  Verify:
  ✓ Login succeeds
  ✓ User account visible
  ✓ My orders accessible

Test 3: Browse Products (2 min)
  [View product list]
  [Click product]
  
  Verify:
  ✓ Products display
  ✓ Details load
  ✓ Price shown
  ✓ Add to cart button present

Test 4: Cart Operations (2 min)
  [Add item to cart]
  [View cart]
  
  Verify:
  ✓ Item added
  ✓ Cart updates
  ✓ Quantity shown
  ✓ Total calculated

Test 5: Checkout (3 min)
  [Proceed to checkout]
  [Enter address]
  [Select shipping]
  [Enter payment]
  [Process payment]
  
  Verify:
  ✓ Checkout flows
  ✓ Payment processes
  ✓ Order confirmed
  ✓ Confirmation email sent

Test 6: Account Access (1 min)
  [View order history]
  
  Verify:
  ✓ Order visible
  ✓ Status shown
  ✓ Order details accessible
  
  Test 7: Logout (1 min)
  [Logout]
  
  Results: ✅ E-commerce fully operational

Example 5: SaaS Dashboard Smoke Test

Workflow: SaaS application smoke test

Purpose: Verify dashboard and core functionality

Duration: 10 minutes

Test 1: Access Dashboard (1 min)
  [Login]
  [View dashboard]
  
  Verify:
  ✓ Dashboard loads
  ✓ Key metrics visible
  ✓ No loading errors

Test 2: Core Metrics (2 min)
  [Check widgets]
  
  Verify:
  ✓ Revenue widget: shows number
  ✓ Users widget: shows count
  ✓ Activity widget: shows data
  
Test 3: Data Tables (2 min)
  [View main data table]
  [Scroll/paginate]
  
  Verify:
  ✓ Table loads
  ✓ Data displays
  ✓ Pagination works

Test 4: Reports (2 min)
  [Generate basic report]
  [View results]
  
  Verify:
  ✓ Report generates
  ✓ Data correct
  ✓ Can download

Test 5: Settings (2 min)
  [Access settings]
  [Verify data]
  
  Verify:
  ✓ Settings load
  ✓ Current settings shown
  ✓ Editable

Test 6: Export (1 min)
  [Export data]
  
  Verify:
  ✓ Export completes
  ✓ File downloaded
  
  Results: ✅ SaaS platform operational

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Smoke Test Execution

Before Each Deployment

New release → Package code → Smoke tests

Pass:
✅ → Deploy to staging
  → Deploy to production
  → Proceed with release

Fail:
❌ → STOP
  → Investigate failure
  → Fix issue
  → Re-test
  → Then deploy

Continuous Monitoring

Every 1-2 hours (during business hours):
  [Run smoke test]
  
Pass:
  ✅ All good

Fail:
  🔴 Alert team
  [Check recent changes]
  [Investigate issue]
  [Fix and re-test]

Per-Commit CI/CD

Developer commits code
  ↓
[Build]
  ↓
[Unit tests]
  ↓
[Smoke tests] ← 10 minutes
  ↓
Fail? → Block merge
Pass? → Continue to integration tests

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Smoke Test Content

What To Include

✓ Application startup ✓ Core authentication ✓ Primary business function ✓ Critical integrations ✓ Basic data retrieval ✓ Session management

What To Exclude

✗ Edge cases ✗ Error scenarios ✗ Advanced features ✗ Performance testing ✗ Security testing ✗ Accessibility testing

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Best Practices

✅ Do

• Keep smoke tests fast - Must complete in <15 min

• Test critical paths - Happy path only

• Run frequently - Per-commit minimum

• Make them reliable - No flaky tests

• Fail fast - Stop on first critical failure

• Simple assertions - Just verify it works

• Use dedicated account - Test account for smoke tests

• Alert on failure - Notify immediately

❌ Don't

• Add comprehensive testing - That's regression

• Test edge cases - Keep it simple

• Slow smoke tests - Goal is speed

• Ignore failures - Fix immediately

• Use production data - Test data only

• Mix smoke + regression - Separate test sets

• Manual smoke tests - Automate all

• Delete results - Keep history

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Troubleshooting

Issue: Smoke test takes too long

Symptoms:

• Test suite runs 20+ minutes

• Too slow for per-commit

Solutions:

1. Remove non-critical tests

2. Run efficiently

3. Mock slow operations

4. Reduce data volume

Issue: Smoke test failing but app works

Symptoms:

• Test fails, but feature works in UI

• False failure

Solutions:

1. Check test logic

2. Verify test data

3. Check timing issues

4. Fix or remove test

Issue: Smoke tests not catching issues

Symptoms:

• Tests pass but production broken

• Not comprehensive enough

Solutions:

1. Review critical paths

2. Add more scenarios

3. Run after smoke tests

4. Use integration/regression

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Real-World Examples

Daily Monitoring

Every 2 hours during business hours:
[Run smoke tests]

8:00 AM: ✅ Pass
10:00 AM: ✅ Pass
12:00 PM: ✅ Pass
2:00 PM: ❌ FAIL - Login broken
  [Alert team]
  [Investigate]
  [Find: database connection issue]
  [Fix deployed]
3:30 PM: ✅ Pass - Issue fixed
5:00 PM: ✅ Pass

Deployment Pipeline

1. Developer commits
2. Build (5 min)
3. Smoke tests run (10 min)
   ✅ Pass → Continue
   ❌ Fail → Block merge
4. Integration tests (30 min)
5. Full regression (60 min)
6. Deploy to staging
7. Deploy to production

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Related Topics

• Regression Testing - Comprehensive testing

• End-to-End Testing - User journeys

• Best Practices - Professional standards

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Summary

• Smoke Testing provides quick health checks

• Keep it fast - <15 minutes absolute maximum

• Test critical paths - Only the most important

• Run frequently - Every commit at minimum

• Fail fast - Stop on first critical issue

• Use for gating - Smoke passes before more testing

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Next: Learn about API Workflow Testing for complex API scenarios.