Covering DI, the D of SOLID. IOC tools, TDD and a bit of best practice

1. http://lifetuned.com
http://pikpak.me
Dependency
Inversion
@tommysqueak http://tomphilip.me

2. About
• Dependency Injection
• Service Location
• TDD & Mocking - How they play together nicely
• Auto-mocking
• IOC - Tools, Features, Usage, Pros/Cons, Best
Practice

4. Definition
• High-level modules should not depend
on low-level modules. Both should
depend on abstractions.
• Abstractions should not depend upon
details. Details should depend upon
abstractions.

5. Design Patterns
Dependency Injection
Service Locator

6. Story
As a Customer
I want to change my password
In order to keep my account secure
Scenario
Given I’m an account holder
When I change my password
Then It should ensure it is a strong password
And it should change my password
And it should notify me it has been changed

7. Demo

8. Benefits
• Loose coupling
• Re-use
• Testability

9. Inversion of Control

10. Provide
Dependency Injection
Service Locator

11. Usage
• Registration
• Entry Point

12. Demo

13. Frameworks
•AutoFac
• NInject
• Castle Windsor
• StructureMap
• Unity

14. How They Look

15. A Little Best Practice
• Internal code should not reference
the container directly
• Verify registration with tests
• Constructor Injection over Setter
Injection over Service Location

16. Picture Credits
• http://www.flickr.com/ • http://www.flickr.com/
photos/smil/4196304056/ - photos/gcwest/
Patterns 281385801/ - containers
• http://lostechies.com/
derickbailey/2009/02/11/
solid-development-
principles-in-motivational-
pictures/ - SOLID pictures
• http://www.flickr.com/
photos/kevindean/
4031083510/ - trolley