Stabilize unit and UI tests for SportsTime

SportsTimeTests/Helpers/TestClock.swift

@@ -0,0 +1,48 @@
+//
+//  TestClock.swift
+//  SportsTimeTests
+//
+//  Centralized time utilities for deterministic tests.
+//
+
+import Foundation
+
+enum TestClock {
+    static let timeZone = TimeZone.current
+    static let locale = Locale(identifier: "en_US_POSIX")
+
+    static let calendar: Calendar = {
+        var calendar = Calendar.current
+        calendar.timeZone = timeZone
+        calendar.locale = locale
+        return calendar
+    }()
+
+    static let baseDate: Date = {
+        let components = DateComponents(
+            calendar: calendar,
+            timeZone: timeZone,
+            year: 2026,
+            month: 1,
+            day: 15,
+            hour: 12,
+            minute: 0,
+            second: 0
+        )
+        return calendar.date(from: components) ?? Date(timeIntervalSince1970: 0)
+    }()
+
+    static var now: Date { baseDate }
+
+    static func startOfDay(for date: Date = baseDate) -> Date {
+        calendar.startOfDay(for: date)
+    }
+
+    static func addingDays(_ days: Int, to date: Date = baseDate) -> Date {
+        calendar.date(byAdding: .day, value: days, to: date) ?? date
+    }
+
+    static func addingHours(_ hours: Int, to date: Date = baseDate) -> Date {
+        calendar.date(byAdding: .hour, value: hours, to: date) ?? date
+    }
+}