Chapter 6: Defect Management

Defect Lifecycle

stateDiagram-v2
    [*] --> New
    New --> Assigned
    Assigned --> InProgress
    InProgress --> Fixed
    Fixed --> ReadyForTest
    ReadyForTest --> Verified: Pass
    ReadyForTest --> Reopened: Fail
    Reopened --> Assigned
    Verified --> Closed
    Closed --> [*]

Writing Effective Bug Reports

Good Bug Report Template:

Title: Login fails with email >50 chars

Severity: High
Priority: P1

Steps to Reproduce:
1. Navigate to login page
2. Enter email with 51 characters
3. Enter valid password
4. Click Login

Expected: Login successful
Actual: "Invalid email" error shown

Environment:
- Browser: Chrome 118
- OS: Windows 11

Bug Severity vs Priority

Severity	Priority	Example
High	High	Payment processing fails
High	Low	Typo in help documentation
Low	High	Logo misaligned (before launch)
Low	Low	Minor UI inconsistency

Defect Metrics

def calculate_defect_metrics(defects):
    """Calculate key defect metrics"""
    total = len(defects)
    open_defects = [d for d in defects if d.status != 'Closed']
    
    return {
        'defect_density': total / lines_of_code * 1000,
        'defect_removal_efficiency': (found_in_test / (found_in_test + found_in_prod)) * 100,
        'open_defect_age': avg([d.age_days for d in open_defects])
    }

Key Takeaways

✅ Clear bug reports save time ✅ Track defect lifecycle ✅ Distinguish severity from priority ✅ Use metrics to improve quality

Complete Lab 6 to practice defect management!