Mid-Level
August 19, 2026

Spot the bug: iOS

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

swift
1import XCTest
2@testable import MyApp
3
4final class TimerTests: XCTestCase {
5    func testCountdown() {
6        let countdown = Countdown(seconds: 2)
7        countdown.start()
8        Thread.sleep(forTimeInterval: 3)
9        XCTAssertTrue(countdown.isFinished)
10    }
11}
12

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