Add fake price fetcher for debug mode

SatsPrice/Network/FakePriceFetcher.swift

@@ -0,0 +1,18 @@
+//
+//  FakePriceFetcher.swift
+//  SatsPrice
+//
+//  Created by Terry Yiu on 2/21/24.
+//
+
+#if DEBUG
+import Foundation
+import BigDecimal
+
+/// Fake price fetcher that returns a randomized price. Useful for development testing without requiring a network call.
+class FakePriceFetcher: PriceFetcher {
+    func btcToUsd() async throws -> BigDecimal? {
+        BigDecimal(Double.random(in: 10000...100000))
+    }
+}
+#endif

SatsPrice/Network/PriceFetcherDelegator.swift

@@ -11,8 +11,15 @@ import BigDecimal
 class PriceFetcherDelegator: PriceFetcher {
     private let coinbasePriceFetcher = CoinbasePriceFetcher()
     private let coinGeckoPriceFetcher = CoinGeckoPriceFetcher()
+#if DEBUG
+    private let fakePriceFetcher = FakePriceFetcher()
+#endif
 
-    var priceSource: PriceSource = .coinbase
+    var priceSource: PriceSource
+
+    init(_ priceSource: PriceSource) {
+        self.priceSource = priceSource
+    }
 
     private var delegate: PriceFetcher {
         switch priceSource {
@@ -20,6 +27,10 @@ class PriceFetcherDelegator: PriceFetcher {
             coinbasePriceFetcher
         case .coingecko:
             coinGeckoPriceFetcher
+#if DEBUG
+        case .fake:
+            fakePriceFetcher
+#endif
         }
     }
 

SatsPrice/Network/PriceSource.swift

@@ -0,0 +1,39 @@
+//
+//  PriceSource.swift
+//  SatsPrice
+//
+//  Created by Terry Yiu on 2/20/24.
+//
+
+import Foundation
+
+enum PriceSource: CaseIterable, CustomStringConvertible {
+    
+    static var allCases: [PriceSource] {
+#if DEBUG
+        [.coinbase, .coingecko, .fake]
+#else
+        [.coinbase, .coingecko]
+#endif
+    }
+
+    case coinbase
+    case coingecko
+
+#if DEBUG
+    case fake
+#endif
+
+    var description: String {
+        switch self {
+        case .coinbase:
+            "Coinbase"
+        case .coingecko:
+            "CoinGecko"
+#if DEBUG
+        case .fake:
+            "Fake"
+#endif
+        }
+    }
+}