Dylan Maryk - How can my unit and UI tests not suck?

In this talk we'll go through some tips for improving your unit and UI testing, based on the libraries, setup and processes we've been using.

Dylan is an iOS developer at door2door, working on the future of shared mobility.

Video: https://youtu.be/zQUBSUe_oOk

Transcript

1. Unit and UI Testing on iOS It sucked, so we made it better
2. Unit Tests
3. Why weren’t we writing many tests? • Apple’s test suite offers poor syntax • ✍ They’re difficult to write • They take a long time to write • All-round bad developer experience
4. Our architecture: MVP+ Presenter Business logic Mock view Mock dependency E.g. Networking Mock dependency E.g. User manager Mock delegate
5. What we want to achieve with mocks • Mocking dependencies of the target class ◦ We don’t want to test networking or data storage when we’re testing the target class • Mocking objects “affected by” the target class ◦ We want to test functions of other classes are called ◦ Delegates ◦ Views
6. New libraries! • Quick + Nimble ◦ Quick: Syntax based on RSpec, readable tests ◦ Nimble: Readable, feature-rich assertions • Cuckoo ◦ Easy mocking of dependencies and protocols ◦ Verify that functions of mocks are called
7. Example of Quick + Nimble
8. Cuckoo: Mocking dependencies + stubbing
9. Cuckoo: Verify statements
10. Top tips! • ➗ Separate and test only your business logic • Force unwrap: don’t worry about null safety • Let your tests influence your dependency structure
11. UI Tests
12. Original problem • No automated method of testing that flows through the app work as expected end-to-end • ⚒ Relied solely on manual testing, in particular to test the core flow before a release
14. Positives • Automation of going through a few of our core flows would save a large amount of developer time • During the development of specific features it would help to ensure that the UX always behaves as expected
15. Negatives • Sometimes a bit flaky • Running all the tests is slow
16. New library: Succulent • ⏺ Records and replays network requests • ⏯ Removes flakiness of performing real requests on every run
22. Top tips! • Test only your core flows • Reset any cached data • Avoid network requests where possible • Consider not running tests on CI on every commit
23. Links • Quick: github.com/Quick/Quick • Nimble: github.com/Quick/Nimble • Cuckoo: github.com/Brightify/Cuckoo • Succulent: github.com/cactuslab/Succulent • Articles: medium.com/@dylanmaryk • Twitter: twitter.com/DylanMaryk
24. Thank you!