Swift Quality Control & Assurance 4

Question 1

In Swift, what is 'dependency injection' and why is it important for testability?

Accepted Answer

Passing dependencies into an object rather than creating them internally, enabling substitution in tests

Answer

Dependency injection passes dependencies (like network clients or databases) from outside, allowing tests to supply mock substitutes instead of real implementations.

Question 2

What is snapshot testing in Swift iOS development primarily used for?

Accepted Answer

Capturing and comparing UI renderings to detect visual regressions

Answer

Snapshot testing captures a reference image of a UI component and compares future renders against it to catch unintended visual changes.

Question 3

Which sanitizer in Xcode detects when Swift code accesses memory it no longer owns?

Accepted Answer

Address Sanitizer

Answer

Address Sanitizer detects memory errors like use-after-free and buffer overflows by tracking memory access patterns at runtime.

Question 4

In the context of Swift QA, what does 'regression testing' mean?

Accepted Answer

Re-running existing tests to ensure past bugs have not re-appeared after changes

Answer

Regression testing runs previously passing tests after code changes to verify that existing functionality has not been broken.

Question 5

Which XCTest method is called once before ALL test methods in a test class run?

Accepted Answer

class func setUp()

Answer

The class-level `class func setUp()` is called once before any instance test methods run, unlike instance `setUp()` which runs before each test.

Swift Practice Test

Swift Practice Test

Swift Quality Control & Assurance 4