# Spot the bug: iOS

> One snippet. Find the bug, or prove there isn't one.

Daily challenge: 2026-08-19 (UTC) · Mid-Level

```swift
import XCTest
@testable import MyApp

final class TimerTests: XCTestCase {
    func testCountdown() {
        let countdown = Countdown(seconds: 2)
        countdown.start()
        Thread.sleep(forTimeInterval: 3)
        XCTAssertTrue(countdown.isFinished)
    }
}

```

## Your verdict

- Security flaw
- Logic bug
- Code style
- No issue

One attempt per day. The answer shows up right after.

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