Introduce KeyStore protocol in order to provide specialized key store implementations for tests

With the DictBasedKeychain the main AppKeychain is not influenced by tests. The previous implementation led to an empty Keychain requiring a new setup of the simulator.

passKit/Helpers/AppKeychain.swift

@@ -8,7 +8,7 @@
 
 import KeychainAccess
 
-public class AppKeychain {
+public class AppKeychain: KeyStore {
 
     public static let shared = AppKeychain()
     

passKit/Helpers/KeyStore.swift

@@ -0,0 +1,19 @@
+//
+//  KeyStore.swift
+//  passKit
+//
+//  Created by Danny Moesch on 20.07.19.
+//  Copyright © 2019 Bob Sun. All rights reserved.
+//
+
+import Foundation
+
+public protocol KeyStore {
+    func add(data: Data?, for key: String)
+    func add(string: String?, for key: String)
+    func contains(key: String) -> Bool
+    func get(for key: String) -> Data?
+    func get(for key: String) -> String?
+    func removeContent(for key: String)
+    func removeAllContent()
+}

passKit/Models/PGPAgent.swift

@@ -12,15 +12,21 @@ import KeychainAccess
 import Gopenpgpwrapper
 
 public class PGPAgent {
+
+    private let keyStore: KeyStore
+
+    public init(keyStore: KeyStore = AppKeychain.shared) {
+        self.keyStore = keyStore
+    }
     
     public var pgpKeyID: String?
     // PGP passphrase
     public var passphrase: String? {
         set {
-            AppKeychain.shared.add(string: newValue, for: "pgpKeyPassphrase")
+            keyStore.add(string: newValue, for: "pgpKeyPassphrase")
         }
         get {
-            return AppKeychain.shared.get(for: "pgpKeyPassphrase")
+            return keyStore.get(for: "pgpKeyPassphrase")
         }
     }
     
@@ -68,12 +74,12 @@ public class PGPAgent {
         }
         
         // Read the key data from keychain.
-        guard let pgpKeyData: Data = AppKeychain.shared.get(for: keyType.getKeychainKey()) else {
+        guard let pgpKeyData: Data = keyStore.get(for: keyType.getKeychainKey()) else {
             throw AppError.KeyImport
         }
         
         // Remove the key data from keychain temporary, in case the following step crashes repeatedly.
-        AppKeychain.shared.removeContent(for: keyType.getKeychainKey())
+        keyStore.removeContent(for: keyType.getKeychainKey())
         
         // Try GopenpgpwrapperReadKey first.
         if let key = GopenpgpwrapperReadKey(pgpKeyData) {
@@ -83,7 +89,7 @@ public class PGPAgent {
             case .PRIVATE:
                 self.privateKey = key
             }
-            AppKeychain.shared.add(data: pgpKeyData, for: keyType.getKeychainKey())
+            keyStore.add(data: pgpKeyData, for: keyType.getKeychainKey())
             return
         }
         
@@ -98,7 +104,7 @@ public class PGPAgent {
             case .PRIVATE:
                 self.privateKeyV2 = key
             }
-            AppKeychain.shared.add(data: pgpKeyData, for: keyType.getKeychainKey())
+            keyStore.add(data: pgpKeyData, for: keyType.getKeychainKey())
             return
         }
         
@@ -107,19 +113,19 @@ public class PGPAgent {
     
     public func initPGPKey(from url: URL, keyType: PgpKey) throws {
         let pgpKeyData = try Data(contentsOf: url)
-        AppKeychain.shared.add(data: pgpKeyData, for: keyType.getKeychainKey())
+        keyStore.add(data: pgpKeyData, for: keyType.getKeychainKey())
         try initPGPKey(keyType)
     }
     
     public func initPGPKey(with armorKey: String, keyType: PgpKey) throws {
         let pgpKeyData = armorKey.data(using: .ascii)!
-        AppKeychain.shared.add(data: pgpKeyData, for: keyType.getKeychainKey())
+        keyStore.add(data: pgpKeyData, for: keyType.getKeychainKey())
         try initPGPKey(keyType)
     }
     
     public func initPGPKeyFromFileSharing() throws {
-        try KeyFileManager.PublicPgp.importKeyAndDeleteFile()
-        try KeyFileManager.PrivatePgp.importKeyAndDeleteFile()
+        try KeyFileManager.PublicPgp.importKeyAndDeleteFile(keyHandler: keyStore.add)
+        try KeyFileManager.PrivatePgp.importKeyAndDeleteFile(keyHandler: keyStore.add)
         try initPGPKeys()
     }
     
@@ -167,8 +173,8 @@ public class PGPAgent {
     }
     
     public func removePGPKeys() {
-        AppKeychain.shared.removeContent(for: PgpKey.PUBLIC.getKeychainKey())
-        AppKeychain.shared.removeContent(for: PgpKey.PRIVATE.getKeychainKey())
+        keyStore.removeContent(for: PgpKey.PUBLIC.getKeychainKey())
+        keyStore.removeContent(for: PgpKey.PRIVATE.getKeychainKey())
         passphrase = nil
         publicKey = nil
         privateKey = nil