agile engineering practices – a short overview
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Agile Engineering Practices – a Short Overview
Dr. Serhiy Yevtushenko, 08 May 2014
Introduction
• Goal – short overview about existing engineering practices
• Agile Methods – Scrum, XP, Kanban, FDD, DSDM, …
• Practice – software development practices applied within methods – Some methods (not all) have recommended set of
practices
• One Slide per practice
History – XP & FDD Extreme Programming Feature Driven
Development
Project size 3-12 2 – 250
Units of planning User Story Feature
Code Ownership Collective Individual
Domain Modeling Shared Metaphor Color Modeling
Collaborative Construction
Pair Programming Formal Inspection (on many levels)
Development Testing Unit Testing/Test driven Development
Unit testing
Integration Testing Automated Acceptance Testing
Manual Testing
Builds Continuous Integration Daily Builds
Practices/Level of Feedback
Practice Feedback Time
Pair Programming/Code Review/Formal Inspection
From seconds to 1-2 days
Unit Testing From minutes to tens of minutes
Builds/Continuous Integration 10 minutes – daily
Integration Test/Acceptance Tests Hour(s) – Days
Frequent Releases/Continuous Delivery Tens per day – 1 per quartal
Collaborative construction
Pair Programming
• Joint problem solving &
checking
• Requires coordination of
developers schedule
• Exhaustive
• May not function with
certain pairs
Formal Inspection
• Most formal Code Review
style – with checklists &
metrics tracking
• Most effective & most
heavyweight
• Lightweight code reviews
with systems – viable
alternative
Rotation
• Forced postponed code
review
• Saves times for code
review meetings
• Requires unit testing in
place for functioning
Code Review
• Less coordination required
• Could synchronous and
asynchronous
• Good systems for
distributed code reviews
currently available
Unit Testing
• Two major styles – Stated Based Testing – Interaction Based Testing
• Property-based testing (a-la QuickChecks) is currently being
explored
• Difficulty varies – Class without dependencies (easy) – … – GUI code – Legacy code – Asynchronous Code
Test Driven Development
THINK ! What is the best way to complete the code?
TEST! Add a small failing test
IMPLEMENT! Add production code, so all tests
will pass REFACTOR! Maximally simplify the code
Behaviour Driven Development
• Based on Test Driven Development
• Different language is used for expressing tests – Behaviour instead of Test – Should instead of Assert
• Suits good for workflow tests – Given – When – Then
• Tests: – (a little bit) better documented – more higher level compared to TDD
Acceptance Testing/Specification by Example
• Requirements specification intermixed with examples (in tabular form)
• Focus on doing right things, instead of doing things right
• Most problematic practice in implementation – Tests are easy to create
– Hard to debug & maintain, long to run
– Number of framework exists • They do not always pull their weight
– Business Users involvement is the hardest problem
• Should be supported on architecture level for success
Exploratory Testing
• Skillful manual testing
• Test design and test execution at the same time
• Sophisticated, thoughtful approach to “ad-hoc” testing
Polyglot Programming & Domain Specific Languages
• New Generation of software development languages
– Groovy, Clojure, Scale, …
• Well-suited for Domain-Specific Languages (DSL)
• Suitable for builds and environment scripting
• Usage of several languages on the same project could be more productive & beneficial
– Unit Tests Code is more compact in scripting languages
Continuous Integration
Continuous Testing
• Let’s run tests on every save
• „Continuous Integration“ for individual developer
Static Code Checking and Monitoring
Agile Databases
• DB Sandbox – DB instance per Developer
• In Memory DB for testing
• Automatic propagation of DB Schema Changes
• Refactoring Databases
• Unit Testing DB Code
• Test Driven Development for Databases
• No SQL – “schemaless” DB
Lightweight Domain Modeling
Continuous Delivery
Q & A
Dr. Serhiy Yevtushenko
codecentric AG An der Welle 3 60322 Frankfut
http://asffm.blogspot.de