2 files changed, 19 insertions, 70 deletions
diff --git a/ios/RelayCache/CachedRelays.swift b/ios/RelayCache/CachedRelays.swift
index 6ff9c36091..499eb9cde3 100644
--- a/ios/RelayCache/CachedRelays.swift
+++ b/ios/RelayCache/CachedRelays.swift
@@ -10,15 +10,15 @@ import Foundation
 import MullvadREST
 
 /// A struct that represents the relay cache on disk
-public struct CachedRelays: Codable {
+public struct CachedRelays: Codable, Equatable {
     /// E-tag returned by server
-    public var etag: String?
+    public let etag: String?
 
     /// The relay list stored within the cache entry
-    public var relays: REST.ServerRelaysResponse
+    public let relays: REST.ServerRelaysResponse
 
     /// The date when this cache was last updated
-    public var updatedAt: Date
+    public let updatedAt: Date
 
     public init(etag: String? = nil, relays: REST.ServerRelaysResponse, updatedAt: Date) {
         self.etag = etag
diff --git a/ios/RelayCache/RelayCache.swift b/ios/RelayCache/RelayCache.swift
index 3c5ceb3a20..abce823786 100644
--- a/ios/RelayCache/RelayCache.swift
+++ b/ios/RelayCache/RelayCache.swift
@@ -8,30 +8,26 @@
 
 import Foundation
 import MullvadREST
+import MullvadTypes
 
 public final class RelayCache {
-    /// Cache file location.
-    let cacheFileURL: URL
+    private let fileCache: any FileCacheProtocol<CachedRelays>
 
-    /// Location of pre-bundled relays file.
-    let prebundledRelaysFileURL: URL
-
-    /// Initialize cache with default cache file location in app group container.
-    public init?(securityGroupIdentifier: String) {
-        guard let containerURL = FileManager.default.containerURL(
-            forSecurityApplicationGroupIdentifier: securityGroupIdentifier
-        ), let prebundledRelaysFileURL = Bundle(for: Self.self)
-            .url(forResource: "relays", withExtension: "json") else { return nil }
+    /// Designated initializer
+    public init(cacheDirectory: URL) {
+        fileCache = FileCache(fileURL: cacheDirectory.appendingPathComponent("relays.json", isDirectory: false))
+    }
 
-        cacheFileURL = containerURL.appendingPathComponent("relays.json", isDirectory: false)
-        self.prebundledRelaysFileURL = prebundledRelaysFileURL
+    /// Initializer that accepts a custom FileCache implementation. Used in tests.
+    init(fileCache: some FileCacheProtocol<CachedRelays>) {
+        self.fileCache = fileCache
     }
 
     /// Safely read the cache file from disk using file coordinator and fallback to prebundled
     /// relays in case if the relay cache file is missing.
     public func read() throws -> CachedRelays {
         do {
-            return try readDiskCache()
+            return try fileCache.read()
         } catch {
             if error is DecodingError || (error as? CocoaError)?.code == .fileReadNoSuchFile {
                 return try readPrebundledRelays()
@@ -43,63 +39,16 @@ public final class RelayCache {
 
     /// Safely write the cache file on disk using file coordinator.
     public func write(record: CachedRelays) throws {
-        var result: Result<Void, Error>?
-        let fileCoordinator = NSFileCoordinator(filePresenter: nil)
-
-        let accessor = { (fileURLForWriting: URL) in
-            result = Result {
-                let data = try JSONEncoder().encode(record)
-                try data.write(to: fileURLForWriting)
-            }
-        }
-
-        var error: NSError?
-        fileCoordinator.coordinate(
-            writingItemAt: cacheFileURL,
-            options: [.forReplacing],
-            error: &error,
-            byAccessor: accessor
-        )
-
-        if let error {
-            result = .failure(error)
-        }
-
-        try result?.get()
-    }
-
-    /// Safely read the cache file from disk using file coordinator.
-    private func readDiskCache() throws -> CachedRelays {
-        var result: Result<CachedRelays, Error>?
-        let fileCoordinator = NSFileCoordinator(filePresenter: nil)
-
-        let accessor = { (fileURLForReading: URL) in
-            result = Result {
-                let data = try Data(contentsOf: fileURLForReading)
-                return try JSONDecoder().decode(CachedRelays.self, from: data)
-            }
-        }
-
-        var error: NSError?
-        fileCoordinator.coordinate(
-            readingItemAt: cacheFileURL,
-            options: [.withoutChanges],
-            error: &error,
-            byAccessor: accessor
-        )
-
-        if let error {
-            result = .failure(error)
-        }
-
-        return try result!.get()
+        try fileCache.write(record)
     }
 
     /// Read pre-bundled relays file from disk.
     private func readPrebundledRelays() throws -> CachedRelays {
+        guard let prebundledRelaysFileURL = Bundle(for: Self.self).url(forResource: "relays", withExtension: "json")
+        else { throw CocoaError(.fileNoSuchFile) }
+
         let data = try Data(contentsOf: prebundledRelaysFileURL)
-        let relays = try REST.Coding.makeJSONDecoder()
-            .decode(REST.ServerRelaysResponse.self, from: data)
+        let relays = try REST.Coding.makeJSONDecoder().decode(REST.ServerRelaysResponse.self, from: data)
 
         return CachedRelays(
             relays: relays,