The top iOS app testing frameworks include Appium, Detox, EarlGrey, XCUITest, and OCMock. Appium is a popular open-source tool that supports native, hybrid, or mobile apps on multiple platforms, while Detox is a JavaScript-based framework for React Native applications only. EarlGrey is an open-source iOS UI automation framework that provides synchronization features similar to Espresso's. XCUITest is a test automation framework used for UI testing of mobile apps and web applications on iOS devices, and OCMock provides a way to create stub objects in iOS app unit tests. The choice of framework depends on the developer's needs, experience with other languages, and the specific tasks required. Sauce Labs provides access to simulated and physical iOS devices and configurations for easy testing.