Make the remote settings hook usable within the app extensions. (#4342)

UnitTests/Sources/RemotePreferenceTests.swift

@@ -0,0 +1,48 @@
+//
+// Copyright 2023, 2024 New Vector Ltd.
+//
+// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+// Please see LICENSE files in the repository root for full details.
+//
+
+import XCTest
+
+@testable import ElementX
+
+class RemotePreferenceTests: XCTestCase {
+    func testOverrideAndReset() {
+        let preference = RemotePreference(0)
+        XCTAssertEqual(preference.publisher.value, 0)
+        XCTAssertFalse(preference.isRemotelyConfigured)
+        
+        preference.applyRemoteValue(1)
+        XCTAssertEqual(preference.publisher.value, 1)
+        XCTAssertTrue(preference.isRemotelyConfigured)
+        
+        preference.applyRemoteValue(2)
+        XCTAssertEqual(preference.publisher.value, 2)
+        XCTAssertTrue(preference.isRemotelyConfigured)
+        
+        preference.reset()
+        XCTAssertEqual(preference.publisher.value, 0)
+        XCTAssertFalse(preference.isRemotelyConfigured)
+    }
+    
+    func testOptionalOverride() {
+        let preference: RemotePreference<String?> = .init("Hello")
+        XCTAssertEqual(preference.publisher.value, "Hello")
+        XCTAssertFalse(preference.isRemotelyConfigured)
+        
+        preference.applyRemoteValue("World")
+        XCTAssertEqual(preference.publisher.value, "World")
+        XCTAssertTrue(preference.isRemotelyConfigured)
+        
+        preference.applyRemoteValue(nil)
+        XCTAssertEqual(preference.publisher.value, nil)
+        XCTAssertTrue(preference.isRemotelyConfigured)
+        
+        preference.reset()
+        XCTAssertEqual(preference.publisher.value, "Hello")
+        XCTAssertFalse(preference.isRemotelyConfigured)
+    }
+}