feat: Working on mocks and mock storage.

Sources/DatabaseClient/PurchaseOrders.swift

@@ -22,3 +22,74 @@ extension PurchaseOrder.Create: Content {}
 extension DatabaseClient.PurchaseOrders: TestDependencyKey {
   public static let testValue: DatabaseClient.PurchaseOrders = Self()
 }
+
+#if DEBUG
+  typealias PurchaseOrderMockStorage = MockStorage<
+    PurchaseOrder,
+    PurchaseOrder.Create,
+    Void,
+    Void,
+    Void
+  >
+
+  public extension DependencyValues {
+    var purchaseOrderID: PurchaseOrderIDGenerator {
+      get { self[PurchaseOrderIDGenerator.self] }
+      set { self[PurchaseOrderIDGenerator.self] = newValue }
+    }
+  }
+
+  @DependencyClient
+  public struct PurchaseOrderIDGenerator: Sendable {
+    var nextID: @Sendable () async throws -> Int
+  }
+
+  extension PurchaseOrderIDGenerator: DependencyKey {
+    public static let testValue: PurchaseOrderIDGenerator = .liveValue
+
+    public static var liveValue: Self {
+      let counter = Counter()
+      return .init(nextID: { await counter.nextID() })
+    }
+
+    actor Counter {
+      private var count: Int
+
+      init(starting: Int = 1) {
+        self.count = starting
+      }
+
+      func nextID() async -> Int {
+        count += 1
+        return count
+      }
+    }
+  }
+
+  // private extension PurchaseOrderMockStorage {
+  //   static func make(_ mocks: [PurchaseOrder]) -> Self {
+  //     @Dependency(\.date.now) var now
+  //     @Dependency(\.purchaseOrderID) var purchaseOrderID
+  //
+  //     return .init(
+  //       mocks,
+  //       create: { model in
+  //         try await PurchaseOrder(
+  //           id: purchaseOrderID.nextID(),
+  //           workOrder: model.workOrder,
+  //           materials: model.materials,
+  //           customer: model.customer,
+  //           truckStock: model.truckStock,
+  //           createdBy: model.createdForID,
+  //           createdFor: model.createdForID,
+  //           vendorBranch: .i
+  //
+  //         )
+  //       },
+  //       update: { _, _ in
+  //         fatalError()
+  //       }
+  //     )
+  //   }
+  // }
+#endif