Bowling Game Kata — An Objective-C version of the Bowling Game Kata, designed to teach Test Driven Development. See description in Xcode TDD 101 with the Bowling Game Kata.
OCHamcrest — A better way to write test assertions, and a framework for creating your own assertions. The Objective-C version of Hamcrest for iOS and OS X:
OCMockito — A better way to write test mock objects. The Objective-C version of Mockito for iOS and OS X:
Unit Test Template for Xcode 4 — An improvement over Apple’s. See description in Warning: Don’t Use Apple’s Unit Test Template.