add stubs, fix typo

ZcashLightClientKitTests/utils/FakeService.swift

@@ -18,6 +18,10 @@ struct LightWalletServiceMockResponse: LightWalletServiceResponse {
 }
 
 class MockLightWalletService: LightWalletService {
+    func fetchUTXOs(for tAddress: String, result: @escaping (Result<[UnspentTransactionOutputEntity], LightWalletServiceError>) -> Void) {
+        
+    }
+    
     
     
     private var service = LightWalletGRPCService(channel: ChannelProvider().channel())

ZcashLightClientKitTests/utils/Stubs.swift

@@ -81,6 +81,10 @@ class MockRustBackend: ZcashRustBackendWelding {
         false
     }
     
+    static func deriveTransparentPrivateKeyFromSeed(seed: [UInt8]) throws -> String? {
+        nil
+    }
+    
     static func initAccountsTable(dbData: URL, exfvks: [String]) throws -> Bool {
         false
     }