testing_the_impossible.txt

Testing the Impossible

Will be going through Copycopter client.  What is that?
  * write place holders in code where things are uploaded to copycopter
  * anyone can edit from copycopter
  * copycopter changes pushed back to app
  
Copyclient requirements (when they built it):
  * automatic
  * easy to setup
  * cannot affect production performance

Copyclient features:
  * 100% test driven

Don't mix concerns.  Separation of Concerns:
  * single responsibility principle:  every object should have a single responsibility that is defined by its class.  
    * A responsibility is a reason for change.
  * the more things you have to test, the harder, slower, and more confusing it becomes

Inherit Less:
  * cannot test sub-class without testing super-class

Prefer composition to inheritance:
  * things are not usually hierarchal

Don't Depend on Concretions:
  * Dependency Inversion Principle: high level modules should not depend on low level modules
  * dependency injection: wiki this to learn more

Avoid Soup

Create Seams:
  * composed methods that support dependency injection

Testing Design:
  * test scope:
    * unit, component, isolation
    * functional, acceptance, integration, full stack
  * restrict fixture scope:
    * use fresh fixtures - create what you need for test in the test
  * avoid test helpers
    * test doubles:
      * stubs, mocks, proxies, and fakes
      * USE FAKES:
        * easier to be DRY, easier to be strict
        * easy to distribute / share with others

Rails:
  * stay generic:
    * use middleware when possible
    * avoid monkey patches
    * keep business logic outside engine parts
    * use Railties only for configuration/initialization
  * integration test
    * generate a rails app
    * install your gem
    * exercise major paths
    * boot a server process if you need to
    * test across several versions
  * isolation tests:
    * unit test components without Rails
    * don't even load ActiveSupport
    * test Rails-specific components separately
    * use fakes

Don't be afraid