What is your iOS testing strategy?

Direct answer

What a strong answer covers

How it works

Fast tests cover models, view models, and formatting logic with dependencies injected through protocols: a fake clock, a fake HTTP client that returns canned responses, an in-memory persistence store. Integration tests exercise the real persistence layer against a temporary store and the real decoding against recorded API fixtures. Snapshot tests catch unintended visual changes in components. A short XCUITest suite drives the critical journeys on a simulator in CI and nothing more, because UI tests are slow and brittle. Swift Testing or XCTest with async support handles concurrency without sleeps.

Example

The CheckoutViewModel is tested with a fake PaymentClient that fails on the second call, asserting that the UI state shows the retry option and that the order is not marked paid. A SwiftData integration test inserts three orders into an in-memory container and checks the unpaid predicate. One XCUITest signs in, adds an item, and completes checkout against a mock server started by the test target.

Common mistakes

• Sleeping in tests to wait for async work instead of awaiting it.
• Depending on a live backend so tests fail whenever staging is down.
• Covering every screen with XCUITests and ending with a two-hour flaky suite.

A useful answer structure

Answer from your own work.

Do not memorise a script: use only examples you can explain honestly in follow-up questions.