On the Care and Feeding of Feedback Cycles Elisabeth Hendrickson

Blog: testobsessed.com

Twitter: @testobsessed

Slides Last updated November 1, 2013

copyright © 2013 Elisabeth Hendrickson

Available from: http://www.slideshare.net/ehendrickson/presentations

Who Am I?

Author Recovering Consultant

Director, Quality Engineering

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What Do We Need Feedback On?

Implementation

Actual Need

Intentions

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Feedback Enables Steering

Observe

Orient

Decide

Act OODA

Plan

Do

Check

Act PDCA

Build

Measure Learn

Lean Startup

The Problem with Long Feedback Latency

Reference: Peter Senge, Fifth Discipline

A Traditional Long Feedback Cycle (and why no one does this anymore)

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Release

First opportunity to see if intentions match implementation

18 month dev cycle

First opportunity to see if implementation matches need

Implement

Test

Design

Analyze

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Speculation Buildup Sp

ecul

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Analyze Design Implement Stabilize Big Bang Release

Every. Single. Time.

Empirical Evidence

speculation!

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Time Value of Information

A piece of information today is worth more

than that same information tomorrow

Agile eliminates speculation buildup…

Spec

ulat

ion

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When “Done” isn’t Really Done

Spec

ulat

ion

Iterations…

Stabilize

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Example of Feedback Loops

Automated Unit Tests

Automated System Tests

CI build w/ tests

Statistical analysis of production metrics

Manual scripted regression testing

Exploring

Customer Opinion

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A Recipe for Fast-and-Complete Feedback

•  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.

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Tightening a Feedback Cycle

spec or story Source

Control code

test

deploy

Observe results Generate ideas

Work in Small Pieces

story

Integrate and Test Locally

code and test

Red

Green Clean

TDD

Source Control

Automate to Eliminate Wait States

test

deploy

Long Running Automated Tests?

•  Remove duplication

•  Drive tests to lowest level

•  Run in parallel

Tighten Feedback Loops (Example)

Code Review

Check in on Private

Branch

Unit Test

Merge Unit Test System

Test

System Test in

Local Env

Check into Master

Run local tests

CI Runs All Tests Pair

BEFORE: days - weeks

AFTER: mins - hours

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Make Feedback Visible

Further Reading