Presented at Flowcon SF on Nov 1, 2013 Nothing interrupts the continuous flow of value like bad surprises that require immediate attention: major defects; service outages; support escalations; or even scrapping just-completed capabilities that don't actually meet business needs. You already know that the sooner you can discover a problem, the sooner and more smoothly you can remedy it. Agile practices involve testing early and often. However feedback comes in many forms, only some of which are traditionally considered testing. Continuous integration, acceptance testing with users, even cohort analysis to validate business hypotheses are all examples of feedback cycles. This talk examines the many forms of feedback, the questions each can answer, and the risks each can mitigate. We'll take a fresh look at the churn and disruption created by having high feedback latency, when the time between taking an action and discovering its effect is too long. We'll also consider how addressing "bugs" that may not be detracting from the actual business value can distract us from addressing real risks. Along the way we'll consider fundamental principles that you can apply immediately to keep your feedback cycles healthy and happy.

1. On the Care and Feeding
of Feedback Cycles
Elisabeth Hendrickson
Blog: testobsessed.com
Twitter: @testobsessed
Available from:
http://www.slideshare.net/ehendrickson/presentations
Slides Last updated November 1, 2013
copyright © 2013 Elisabeth Hendrickson

2. Author
Recovering
Consultant
Director, Quality Engineering
Elisabeth Hendrickson @testobsessed
Who Am I?

3. Intentions
Implementation
Actual Need
Elisabeth Hendrickson @testobsessed
What Do We Need Feedback On?

4. Feedback Enables Steering
Plan
PDCA
Do
Check
Lean
Startup
Learn
Observe
Act
OODA
Decide
Orient
Measure
Elisabeth Hendrickson @testobsessed
Act
Build

5. The Problem with Long Feedback Latency
Reference: Peter Senge, Fifth Discipline

6. A Traditional Long Feedback Cycle
(and why no one does this anymore)
18 month dev cycle
Design
Implement
First opportunity to see
if intentions match
implementation
First opportunity to see
if implementation
matches need
Test
Release
Elisabeth Hendrickson @testobsessed
Analyze

7. Analyze
Design
Implement
Stabilize
Big Bang
Release
Elisabeth Hendrickson @testobsessed
Speculation
Speculation Buildup

8. speculation!
Every. Single. Time.
Elisabeth Hendrickson @testobsessed
Empirical
Evidence

9. Time Value of Information
A piece of information
today is worth more
than that same
information tomorrow

10. Elisabeth Hendrickson @testobsessed
Speculation
Agile eliminates speculation buildup…

11. Stabilize
Iterations…
Elisabeth Hendrickson @testobsessed
Speculation
When “Done” isn’t Really Done

12. Example of Feedback Loops
Automated System Tests
CI build w/ tests
Exploring
Manual scripted regression testing
Statistical analysis of production metrics
Customer Opinion
Elisabeth Hendrickson @testobsessed
Automated Unit Tests

13. +
+
• Automatically check that the emerging system
behaves as expected with every new change.
• Explore both to discover other risks and to
verify that the checks are sufficient.
• Release early and often.
Elisabeth Hendrickson @testobsessed
A Recipe for Fast-and-Complete Feedback

14. Tightening a Feedback Cycle
spec or
story
Source
Control
code
Observe results
Generate ideas
test
deploy

15. Work in Small Pieces
story

16. Integrate and Test Locally
Source
Control
code
and test
Red
TDD
Clean
Green

17. Automate to Eliminate Wait States
Long Running
Automated Tests?
• Remove duplication
test
• Drive tests to lowest
level
• Run in parallel
deploy

18. Tighten Feedback Loops (Example)
System
Test in
Local Env
Check in
on Private
Branch
Unit Test
Merge
Unit Test
Code
Review
System
Test
AFTER: mins - hours
Pair
Run local
tests
Check into
Master
CI Runs All
Tests
Elisabeth Hendrickson @testobsessed
BEFORE: days - weeks

19. Make Feedback Visible

20. Further Reading