QA Testing Methodology Skill

Apply proven test design patterns for comprehensive test coverage.

Test Case Design Order

Always design tests in this order:

1. Happy Path - Main success scenarios
2. Validation Tests - Required fields, format validation
3. Edge Cases - Boundary conditions, limits
4. Error Scenarios - Invalid inputs, system errors
5. Permission Tests - Access control, authorization

Equivalence Partitioning

Divide input data into partitions where all values should behave identically.

Example: Age Input Field (18-65)

Partition	Values	Expected Behavior
Below minimum	0-17	Reject with "Must be 18+"
Valid range	18-65	Accept
Above maximum	66+	Reject with "Maximum age is 65"
Invalid	-1, "abc", empty	Reject with validation error

Test Strategy: Test ONE value from each partition, not every value.

Boundary Value Analysis

Focus testing on boundaries where behavior changes.

Example: Password (8-20 characters)

Boundary	Test Values	Expected
Just below minimum	7 chars	Reject
At minimum	8 chars	Accept
Just above minimum	9 chars	Accept
Just below maximum	19 chars	Accept
At maximum	20 chars	Accept
Just above maximum	21 chars	Reject

Test Prioritization Matrix

Prioritize tests based on risk and frequency:

Priority	Risk	User Impact	Test Frequency
Critical	Data loss, security breach	All users blocked	Every build
High	Feature broken	Major workflow impacted	Every release
Medium	Inconvenient	Workaround available	Weekly
Low	Minor annoyance	Cosmetic issues	Monthly

Accessibility Testing Checklist

Include in every test procedure:

Keyboard Navigation

• All interactive elements focusable with Tab
• Focus order is logical (left-to-right, top-to-bottom)
• Focus indicator is visible
• No keyboard traps

Screen Reader

• All images have alt text
• Form fields have labels
• Error messages announced
• Headings structured correctly (h1 → h2 → h3)

Visual

• Color contrast meets WCAG AA (4.5:1 for text)
• Information not conveyed by color alone
• Text resizable to 200% without loss
• No content flashes more than 3 times/second

Performance Considerations

Note performance during manual testing:

Metric	Acceptable	Needs Investigation
Page load	< 3 seconds	> 3 seconds
Button response	< 100ms	> 300ms
Form submission	< 2 seconds	> 5 seconds
Search results	< 1 second	> 2 seconds

Test Data Guidelines

DO

• Use realistic but fake data
• Document exact test data in test cases
• Use consistent test accounts
• Reset test data between runs when needed

DON'T

• Use production data
• Use generic placeholders ("enter something")
• Share test credentials in plain text
• Assume data from previous tests exists

Test Data Examples

Email: test.user@example.com
Password: Test@1234! (in password manager)
Phone: +1-555-0100 (test range)
Credit Card: 4111-1111-1111-1111 (test card)
Address: 123 Test Street, Test City, TS 12345

Regression Testing

When to run regression tests:

Trigger	Regression Scope
Bug fix	Related feature + integration points
New feature	All features that share data/UI
Dependency update	Full regression
Release candidate	Critical + High priority tests

State-Based Testing

Test all valid state transitions:

Example: Order Status
┌─────────┐     ┌─────────┐     ┌─────────┐     ┌───────────┐
│ Created │ ──▶ │ Pending │ ──▶ │ Shipped │ ──▶ │ Delivered │
└─────────┘     └─────────┘     └─────────┘     └───────────┘
                     │                               │
                     ▼                               ▼
               ┌───────────┐                  ┌────────────┐
               │ Cancelled │                  │  Returned  │
               └───────────┘                  └────────────┘

Test:

• Valid transitions (Created → Pending)
• Invalid transitions (Delivered → Created)
• Edge cases (Cancel while shipping)

Error Message Verification

Check error messages for:

1. Clarity: User understands what went wrong
2. Actionability: User knows how to fix it
3. Tone: Professional, not blaming
4. Security: No sensitive information exposed

Good vs Bad Error Messages

Bad	Good
"Error 500"	"Something went wrong. Please try again."
"Invalid input"	"Email must be in format: name@example.com"
"User not found in database"	"No account found with this email"
"Password must match regex..."	"Password needs 8+ characters with a number"

Cross-Browser Testing Matrix

Minimum browser coverage:

Browser	Desktop	Mobile
Chrome	Latest, Latest-1	Android
Safari	Latest	iOS
Firefox	Latest	-
Edge	Latest	-

Test Documentation Patterns

When to Screenshot

• Initial state before test
• After critical actions
• Error states
• Final/success state
• Any unexpected behavior

Writing Clear Steps

Bad: Click the button Good: Click the blue "Submit" button in the bottom-right of the form

Bad: Enter your details Good: Enter "test@example.com" in the Email field

Bad: Verify it works Good: Verify success message "Order placed successfully" appears

Mobile Testing Considerations

• Test touch targets (minimum 44x44 pixels)
• Test swipe gestures where applicable
• Test orientation changes (portrait ↔ landscape)
• Test with on-screen keyboard visible
• Test with poor network (3G simulation)