Test Diven Development With the VIPER Architecture Presentation: https://www.youtube.com/watch?v=WqmlL37l_1c

1. TDD & VIPER
Made For Each Other
Presented by Lyle Resnick
lyle@cellarpoint.com

2. Rules of Thumb
• Test either the output or the side effects but not
both at the same time
• Output is captured either by result or protocol
• Side effects are captured by properties of
overridden methods

3. What does VIPER
Provide?
• Seams
• Protocols
• A Plan

4. VIPER Classes

5. Viper Classes +

6. Viper Event Sequence
Lots of Seams
Back Arrows are Protocols
Always rendered in the same way

7. The Transaction Report

8. Starting VIPER
• Manually create VIPER Classes
• Create the Connector
• Create minimal ViewController, View Delegate
Adapters, Presenter, UseCase
• Generate VIPER classes from TD Template

9. Start With The View
• Its comfortable
• Start with the IB Injection Tests
• Create Views for all states

10. Create Views For All States
• For One Event
• Not just the happy path
• Nothing, Loading, None, One, Some, Too Many,
Correct, Done
• Incorrect
• Semantic or Systemic Error

11. The Storyboard

12. IB Injection Tests
• Instantiate the ViewController as the SUT
• Repeat This:
• Create a Failing Test
• Layout the Views in IB
• associate with classes and identifiers
• Create and Connect Outlets
• Pass the Test

13. ViewController Tests
• Start with PresenterOutput
• Called by the Presenter
• Instantiate ViewController as the SUT via FakeIBLoader
• Loader sets the views into the cell outlets
• Repeat This:
• Create a Failing Test
• Implement the UseCaseOutput method of interest
• Capture behaviour via View properties or adapter Mocks/Stubs
• Verify and pass the Test

14. Cell Tests
• Populate the Cells
• Repeat This:
• Create a Failing Test
• instantiate a cell
• set the views into the cell outlets
• Add the cell Protocol to the cell and implement the show method
• Call the show method on the cell
• Get the set values
• Verify and pass the Test

15. Presenter Tests
• Start with UseCaseOutput
• Called by the UseCase (or the Transformer)
• Instantiate Presenter as the SUT
• Repeat This:
• Create a Failing Test
• Implement the UseCaseOutput method of interest
• Capture behaviour via ViewController Mocks/Stub
• Verify and pass the Test

16. View Model Tests
• Create the ViewModels for Cells
• Instantiate Presenter as the SUT
• Implement the presenter’s ViewModel collection and public accessors
• Repeat This:
• Create a Failing Test by calling present method
• implement the present method
• Call the UseCaseOutput present method on the Presenter
• Get the set values on the ViewModels
• Verify and pass the Test

17. Table Adapter Tests
• Test the ViewModel access
• Called by the TableView
• Instantiate the TableAdapter as the SUT
• Configure the Presenter
• Repeat This:
• Create a Failing Test
• Call the UITableViewDataSource/Delegate method
• Implement the UITableViewDataSource/Delegate method
• Capture output via calls to SUT
• Verify and pass the Test

18. Transformer Tests
• This is where the action happens
• Allows test of pure algorithm with no conversions
• Instantiate the Transformer as the SUT
• Create Fake Models to stand-in for output
• Implement UseCaseOutput with fake models
• Repeat this:
• Create data sets for cases
• run the transform method
• Verify and pass the Test

19. The Rest of the Tests
• Test the events from
• the ViewController to the Presenter
• the Presenter to the UseCase
• the UseCase to the Transformer
• the Transformer back to the Presenter