W10 Concurrent Class
10/2/2013 1:45:00 PM
"Agile Code Reviews for Better
Software—Sooner"
Presented by:
Mark Hammer
SmartBear Software
Brought to you by:
340 Corporate Way, Suite 300, Orange Park, FL 32073
888-268-8770 ∙ 904-278-0524 ∙ [email protected] ∙ www.sqe.com
Mark Hammer
SmartBear Software
Senior product director at SmartBear Software Mark Hammer speaks and writes about the
software development process with a special emphasis on code review. Mark has more than
twenty years of experience in software product management, previously at global-education
leader Houghton Mifflin Harcourt. He has a strong track record in developing customer-focused
business solutions in both business-to-business and business-to-consumer markets. Mark was
VP of marketing for CompassLearning, an educational software developer.
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Want Higher Quality Software
from Your Agile Team?
Peer Review Works
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Mark Hammer
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Product Mgmt Development QA
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Product Mgmt Development QA
User stories Code Test Plans
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Professional Writers Have Editors
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Industry Metrics
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Measure Industry Average
High Performance Teams
Net Promoter Score 20% > 70%
% defects of total injected found by customer 15% < 2%
% effort spent in finding and fixing defects 50% < 10%
% effort for post-release support 30% < 5%
Unit test code coverage Varies > 80%
Post release defect density 7.5 defects/KLOC
< 0.5 defects/KLOC
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Measure Industry Average
High Performance Teams
Net Promoter Score 20% > 70%
% defects of total injected found by customer 15% < 2%
% effort spent in finding and fixing defects 50% < 10%
% effort for post-release support 30% < 5%
Unit test code coverage Varies > 80%
Post release defect density 7.5 defects/KLOC
< 0.5 defects/KLOC
Bugs found in development are 8-12X less expensive to fix than those found in QA phase
And 30-100X less expensive than bugs that reach customers
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The Curious Case of Missing Code Reviews
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Requirements
Design
Architecture
Discussion Review Review
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Requirements
Design
Architecture
Code
Discussion Review Review N/A
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Requirements Architecture Code Test Plans
Review
Product Mgmt Development QA
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Geographically-distributed teams (main vs. offshore
teams, apprentice – mentor)
CMMI – code review is mandated
FDA – code review is mandated
Embedded systems – very high cost of change
PCI – code review is mandated
Agile teams – fast, convenient way to collaborate,
provides less time-intensive “pair programming”
opportunity
If You Need More Convincing
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Code Review Options
Over-the-Shoulder
Pair Programming
Formal Inspection Meetings?!
Tool
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Over-the-Shoulder
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Over-the-Shoulder
Easy / Free
Interruption
No Info Recorded
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Easy / Free
No Interruption / Remote
Conversation Tracking
Info. Hard to Retrieve
No End?
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Pair Programming
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Pair Programming
No Tools or Workflow
Deep Thought
Big Time Commitment
No Info. Recorded
Too Close
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Why Don’t More Teams Do It?
• It’s hard to do, with no clear perceived
benefits
– Expensive, tedious and time consuming to
do it manually
– Difficult to track threads of communication
– Code review isn’t integrated with source
code management (SCM) tool
– Hard to collaborate with remote members
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Hapless Developer
Reviewers
Version Control
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Largest Peer Code Review Study Ever
• Objectives:
– lightweight vs. formal inspections
– What constitutes an effective review?
• 10-month case study at Cisco
• Cisco MeetingPlace product, teleconferencing
solution
• 3.2 million lines of code
• 2500 reviews
• 50 developers
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Recommendations (Best Practices)
LOC under review < 200, Not to exceed 400
Author preparation with annotations - Self review checklist
Total review time < 60 min. Not to exceed 90
Inspection rate < 300 LOC/hour
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Product Mgmt QA
User stories Code Test Plans
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Requirements Architecture Code Test Plans
Review
Product Mgmt Development QA
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Case Study
• 2011: 70 floating licenses: ~350 developers
• 2013: 130 floating licenses: ~650 team members
• User stories are shared in Word format with entire
team
• Design documents are shared in Powerpoint with
entire team
• Code is shared with entire team
• Test cases are shared in Excel format with entire
team
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Benefits of Cross-Functional Peer Review
• Every member of the extended development team
knows what’s happening
• Problems with user stories, code, and test plans are
found faster
• It forces developers to write readable code (code that
can be read without explanation!)
• Optimization methods/tricks/productive programs
spread faster
• Programmer as a specialist "evolve" faster
• Teams can iterate from story to code to test plan
• It's fun
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The simple fact of knowing your work will be
reviewed by others means you’ll do it better.
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