Quality Metrics

Test Coverage Metrics

Code Coverage Types

• Line Coverage: Percentage of executable lines executed
• Branch Coverage: Percentage of conditional branches taken
• Function Coverage: Percentage of functions/methods called
• Statement Coverage: Percentage of statements executed
• Condition Coverage: Percentage of boolean sub-conditions evaluated

Coverage Targets

Critical Business Logic: 90-100%
Core Application Code: 80-90%
Utility/Helper Code: 70-80%
Configuration/Setup Code: 50-70%

Coverage Tools

• JavaScript: Istanbul, nyc, Jest coverage
• Python: pytest-cov, coverage.py
• Java: JaCoCo, Cobertura
• .NET: dotCover, Coverlet
• Go: go test -cover

Coverage Best Practices

• Focus on meaningful coverage, not just percentage
• Prioritize coverage of critical paths
• Track coverage trends over time
• Set coverage gates in CI/CD
• Review uncovered code regularly

Code Quality Metrics

Cyclomatic Complexity

• Measures code complexity based on control flow
• Higher complexity = harder to test and maintain
• Target: < 10 per function/method

Complexity Levels:
1-10: Simple, low risk
11-20: Moderate complexity, medium risk
21-50: High complexity, high risk
50+: Very high complexity, very high risk

Maintainability Index

• Composite metric combining complexity, volume, and structure
• Scale: 0-100 (higher is better)
• Target: > 70

Maintainability Levels:
85-100: Highly maintainable
70-84: Moderately maintainable
50-69: Difficult to maintain
0-49: Very difficult to maintain

Code Duplication

• Percentage of duplicated code
• Target: < 5%
• High duplication indicates need for refactoring

Code Smells

• Long Methods: Methods > 50 lines
• Large Classes: Classes > 500 lines
• Deep Nesting: Nesting > 4 levels
• Long Parameter Lists: > 4 parameters
• Feature Envy: Methods using other objects more than their own

Technical Debt Ratio

Technical Debt Ratio = Cost to Fix Issues / Cost to Develop New Features
Target: < 5%

Defect Metrics

Defect Density

• Defects per thousand lines of code (KLOC)
• Defects per function point
• Defects per module/component

Defect Density = Total Defects / Size Metric (KLOC, FP)
Target: < 1 defect per KLOC

Defect Removal Efficiency (DRE)

• Percentage of defects found before release
• Higher is better

DRE = (Defects Found Before Release / Total Defects) × 100
Target: > 90%

Defect Leakage

• Percentage of defects found after release
• Lower is better

Defect Leakage = (Defects Found After Release / Total Defects) × 100
Target: < 10%

Defect Age

• Time from defect introduction to detection
• Time from defect detection to resolution

Defect Age = Detection Date - Introduction Date
Resolution Time = Resolution Date - Detection Date
Target: < 7 days for critical defects

Defect Severity Distribution

• Critical: System failure, data loss
• High: Major functionality broken
• Medium: Minor functionality broken
• Low: Cosmetic issues, typos

Defect Trend Analysis

• Track defects over time
• Identify patterns and trends
• Correlate with code changes
• Predict future defect rates

Quality Gates and Acceptance Criteria

Quality Gate Examples

Code Quality Gate:
- Code coverage ≥ 80%
- No critical or high severity defects
- Cyclomatic complexity ≤ 10
- No security vulnerabilities
- All tests passing

Performance Gate:
- p95 response time < 500ms
- Error rate < 0.1%
- Throughput ≥ 1000 RPS
- CPU utilization < 70%

Security Gate:
- No high/critical vulnerabilities
- OWASP Top 10 compliance
- Dependency scan clean
- Authentication/authorization tested

Acceptance Criteria

• Functional Requirements: All features work as specified
• Non-Functional Requirements: Performance, security, usability met
• Test Coverage: Minimum coverage thresholds met
• Defect Standards: No defects above acceptable severity
• Documentation: All documentation complete and accurate

Test Reporting and Dashboards

Test Execution Reports

• Total tests run
• Pass/fail counts and percentages
• Test execution time
• Flaky test identification
• Test failure categorization

Coverage Reports

• Line, branch, function coverage
• Coverage by module/component
• Uncovered code highlighting
• Coverage trends over time
• Coverage comparison between branches

Defect Reports

• Open defects by severity
• Defect trends and patterns
• Defect age distribution
• Defect resolution time
• Defect density by module

Performance Reports

• Response time metrics (p50, p95, p99)
• Throughput metrics
• Error rates
• Resource utilization
• Performance trends over time

Dashboard Elements

• Overall quality score
• Test coverage gauge
• Defect trend chart
• Performance metrics
• Build health status
• Quality gate status

QA KPIs and Metrics Tracking

Process Metrics

• Test Execution Time: Time to run test suite
• Test Automation Rate: Percentage of tests automated
• Test Case Count: Total number of test cases
• Test Case Execution: Number of tests executed per period
• Defect Detection Rate: Defects found per testing hour

Product Metrics

• Defect Escape Rate: Defects found in production
• Mean Time to Detection: Time to find defects
• Mean Time to Resolution: Time to fix defects
• Customer Reported Defects: Defects reported by users
• Test Coverage: Code, feature, and requirement coverage

Team Metrics

• Test Case Productivity: Test cases created per person-hour
• Automation Productivity: Automated tests created per person-hour
• Defect Detection Efficiency: Defects found per person-hour
• Test Execution Efficiency: Tests executed per person-hour

Quality Metrics

• Overall Quality Score: Composite quality metric
• Test Pass Rate: Percentage of passing tests
• Defect Density: Defects per size metric
• Code Quality Score: Based on complexity, duplication, smells
• Performance Score: Based on response time, throughput, errors

Metrics Dashboard

Quality Dashboard:
┌─────────────────────────────────────────┐
│ Overall Quality Score: 87/100          │
├─────────────────────────────────────────┤
│ Test Coverage: 85%                      │
│ ├─ Line: 87%                            │
│ ├─ Branch: 82%                          │
│ └─ Function: 90%                       │
├─────────────────────────────────────────┤
│ Code Quality: 82/100                    │
│ ├─ Complexity: 8.2 avg                  │
│ ├─ Duplication: 3.1%                    │
│ └─ Maintainability: 78                  │
├─────────────────────────────────────────┤
│ Defects: 12 open                        │
│ ├─ Critical: 1                          │
│ ├─ High: 3                              │
│ ├─ Medium: 5                            │
│ └─ Low: 3                               │
├─────────────────────────────────────────┤
│ Performance: 92/100                     │
│ ├─ p95 Response: 420ms                  │
│ ├─ Throughput: 1250 RPS                 │
│ └─ Error Rate: 0.05%                    │
└─────────────────────────────────────────┘

Metrics Collection and Analysis

Data Collection

• Automated collection from CI/CD pipelines
• Integration with test frameworks
• Real-time monitoring and alerts
• Historical data storage
• Data normalization and aggregation

Analysis Techniques

• Trend analysis over time
• Comparison between branches/releases
• Correlation with code changes
• Root cause analysis of quality issues
• Predictive analytics for quality forecasting

Reporting Frequency

• Real-time: Build status, test failures, critical defects
• Daily: Test execution, defect updates, performance metrics
• Weekly: Quality trends, coverage reports, team metrics
• Monthly: Quality scorecards, process improvements, strategic insights
• Quarterly: Quality reviews, goal setting, process optimization

Continuous Improvement

• Identify quality trends and patterns
• Set quality goals and targets
• Track progress toward goals
• Implement process improvements based on metrics
• Celebrate quality achievements