Increase decimal points in order POST-PUT requests to mitigate tax rounding issues (#15957)

Author: iamgabrielma

Modules/Sources/NetworkingCore/Remote/OrdersRemote.swift

@@ -228,6 +228,8 @@ public class OrdersRemote: Remote {
                     params[Order.CodingKeys.createdVia.rawValue] = createdViaValue
                 }
 
+                params[ParameterKeys.decimalPlaces] = OrdersRemote.Defaults.decimalPoints
+
                 return params
             }()
 
@@ -253,7 +255,10 @@ public class OrdersRemote: Remote {
     ///
     public func updateOrder(from siteID: Int64, orderID: Int64, statusKey: OrderStatusEnum, completion: @escaping (Order?, Error?) -> Void) {
         let path = "\(Constants.ordersPath)/" + String(orderID)
-        let parameters = [ParameterKeys.statusKey: statusKey.rawValue]
+        let parameters = [
+            ParameterKeys.statusKey: statusKey.rawValue,
+            ParameterKeys.decimalPlaces: OrdersRemote.Defaults.decimalPoints
+        ]
         let mapper = OrderMapper(siteID: siteID)
 
         let request = JetpackRequest(wooApiVersion: .mark3,
@@ -328,6 +333,9 @@ public class OrdersRemote: Remote {
                                                                                value: cashPaymentChangeDueAmount).toDictionary()]
                 }
 
+                // Add decimal places parameter for better precision
+                params[ParameterKeys.decimalPlaces] = OrdersRemote.Defaults.decimalPoints
+
                 return params
             }()
 
@@ -449,8 +457,9 @@ extension OrdersRemote: POSOrdersRemoteProtocol {
 //
 public extension OrdersRemote {
     enum Defaults {
-        public static let pageSize: Int     = 25
-        public static let pageNumber: Int   = 1
+        public static let pageSize: Int = 25
+        public static let pageNumber: Int = 1
+        public static let decimalPoints: String = "8"
         public static let statusAny: String = "any"
     }
 
@@ -477,6 +486,7 @@ public extension OrdersRemote {
         static let customer = "customer"
         static let product = "product"
         static let createdVia = "created_via"
+        static let decimalPlaces = "dp"
     }
 
     enum ParameterValues {

Modules/Tests/NetworkingTests/Remote/OrdersRemoteTests.swift

@@ -309,6 +309,19 @@ final class OrdersRemoteTests: XCTestCase {
         wait(for: [expectation], timeout: Constants.expectationTimeout)
     }
 
+    func test_updateOrder_status_includes_decimal_places_parameter() throws {
+        // Given
+        let remote = OrdersRemote(network: network)
+
+        // When
+        remote.updateOrder(from: sampleSiteID, orderID: sampleOrderID, statusKey: .pending) { (order, error) in }
+
+        // Then
+        let request = try XCTUnwrap(network.requestsForResponseData.last as? JetpackRequest)
+        let received = try XCTUnwrap(request.parameters["dp"] as? String)
+        assertEqual(received, "8")
+    }
+
     func test_update_order_properly_encodes_shipping_lines_for_removal_from_order() throws {
         // Given
         let remote = OrdersRemote(network: network)
@@ -517,6 +530,20 @@ final class OrdersRemoteTests: XCTestCase {
         XCTAssertNil(request.parameters["meta_data"])
     }
 
+    func test_updateOrder_with_fields_includes_decimal_places_parameter() throws {
+        // Given
+        let remote = OrdersRemote(network: network)
+        let order = Order.fake()
+
+        // When
+        remote.updateOrder(from: sampleSiteID, order: order, giftCard: nil, fields: [.customerNote]) { result in }
+
+        // Then
+        let request = try XCTUnwrap(network.requestsForResponseData.last as? JetpackRequest)
+        let received = try XCTUnwrap(request.parameters["dp"] as? String)
+        assertEqual(received, "8")
+    }
+
     // MARK: - Load Order Notes Tests
 
     /// Verifies that loadOrderNotes properly parses the `order-notes` sample response.
@@ -806,6 +833,20 @@ final class OrdersRemoteTests: XCTestCase {
         XCTAssertNil(request.parameters["created_via"])
     }
 
+    func test_createOrder_includes_decimal_places_parameter() throws {
+        // Given
+        let remote = OrdersRemote(network: network)
+        let order = Order.fake()
+
+        // When
+        remote.createOrder(siteID: 123, order: order, giftCard: nil, fields: []) { result in }
+
+        // Then
+        let request = try XCTUnwrap(network.requestsForResponseData.last as? JetpackRequest)
+        let received = try XCTUnwrap(request.parameters["dp"] as? String)
+        assertEqual(received, "8")
+    }
+
     // MARK: - Delete order tests
 
     func test_delete_order_properly_returns_parsed_order() throws {

Modules/Tests/YosemiteTests/Stores/OrderStoreTests.swift

@@ -1269,6 +1269,7 @@ final class OrderStoreTests: XCTestCase {
             "currency",
             "customer_id",
             "customer_note",
+            "dp",
             "fee_lines",
             "line_items",
             "meta_data",
@@ -1297,6 +1298,7 @@ final class OrderStoreTests: XCTestCase {
             "currency",
             "customer_id",
             "customer_note",
+            "dp",
             "fee_lines",
             "gift_cards",
             "line_items",
@@ -1359,7 +1361,8 @@ final class OrderStoreTests: XCTestCase {
         let expectedKeys = [
             "gift_cards"
         ]
-        assertEqual(expectedKeys, receivedKeys)
+        // Updating an order will also contain `dp` (decimal point), but in this case we're only interested in `gift_cards`
+        XCTAssertTrue(receivedKeys.contains(expectedKeys))
     }
 
     func test_update_order_with_gift_card_returns_notApplied_error_when_error_response_does_not_include_gift_card() throws {

RELEASE-NOTES.txt

@@ -3,6 +3,7 @@
 
 23.0
 -----
+- [*] Increased decimal sensitivity in order creation to mitigate tax rounding issues [https://github.com/woocommerce/woocommerce-ios/pull/15957]
 - [*] Fix initialization of authenticator to avoid crashes during login [https://github.com/woocommerce/woocommerce-ios/pull/15953]
 - [*] Shipping Labels: Made HS tariff number field required in customs form for EU destinations [https://github.com/woocommerce/woocommerce-ios/pull/15946]
 

WooCommerce/Classes/ViewRelated/Orders/Order Creation/EditableOrderViewModel.swift

@@ -2603,7 +2603,7 @@ private extension EditableOrderViewModel {
 }
 
 extension TaxBasedOnSetting {
-    var displayString: String {
+    var displayTaxCalculationHint: String {
         switch self {
         case .customerBillingAddress:
             return NSLocalizedString("editableOrderViewModel.taxBasedOnSetting.customerBillingAddress",

WooCommerce/Classes/ViewRelated/Orders/Order Creation/PaymentSection/OrderPaymentSection.swift

@@ -234,7 +234,7 @@ private extension OrderPaymentSection {
 
     @ViewBuilder var taxBasedOnLine: some View {
         HStack(spacing: Constants.taxBasedOnLineTextPadding) {
-            Text(viewModel.taxBasedOnSetting?.displayString ?? "")
+            Text(viewModel.taxBasedOnSetting?.displayTaxCalculationHint ?? "")
                 .footnoteStyle()
                 .multilineTextAlignment(.leading)
             Text(Localization.taxInformationLearnMore)

WooCommerce/WooCommerceTests/ViewRelated/Orders/Order Creation/EditableOrderViewModelTests.swift

@@ -2379,6 +2379,10 @@ final class EditableOrderViewModelTests: XCTestCase {
     }
 
     func test_order_created_when_tax_based_on_is_customer_billing_address_then_property_is_updated() {
+        // Given
+        let expectedString = NSLocalizedString("Calculated on billing address.", comment: "")
+
+        // When
         stores.whenReceivingAction(ofType: SettingAction.self, thenCall: { action in
             switch action {
             case .retrieveTaxBasedOnSetting(_, let onCompletion):
@@ -2391,10 +2395,15 @@ final class EditableOrderViewModelTests: XCTestCase {
         let viewModel = EditableOrderViewModel(siteID: sampleSiteID,
                                                stores: stores)
 
-        XCTAssertEqual(viewModel.paymentDataViewModel.taxBasedOnSetting?.displayString, NSLocalizedString("Calculated on billing address.", comment: ""))
+        // Then
+        XCTAssertEqual(viewModel.paymentDataViewModel.taxBasedOnSetting?.displayTaxCalculationHint, expectedString)
     }
 
     func test_order_created_when_tax_based_on_is_shop_base_address_then_property_is_updated() {
+        // Given
+        let expectedString = NSLocalizedString("Calculated on shop base address.", comment: "")
+
+        // When
         stores.whenReceivingAction(ofType: SettingAction.self, thenCall: { action in
             switch action {
             case .retrieveTaxBasedOnSetting(_, let onCompletion):
@@ -2407,10 +2416,15 @@ final class EditableOrderViewModelTests: XCTestCase {
         let viewModel = EditableOrderViewModel(siteID: sampleSiteID,
                                                stores: stores)
 
-        XCTAssertEqual(viewModel.paymentDataViewModel.taxBasedOnSetting?.displayString, NSLocalizedString("Calculated on shop base address.", comment: ""))
+        // Then
+        XCTAssertEqual(viewModel.paymentDataViewModel.taxBasedOnSetting?.displayTaxCalculationHint, expectedString)
     }
 
     func test_order_created_when_tax_based_on_is_customer_shipping_address_then_property_is_updated() {
+        // Given
+        let expectedString = NSLocalizedString("Calculated on shipping address.", comment: "")
+
+        // When
         stores.whenReceivingAction(ofType: SettingAction.self, thenCall: { action in
             switch action {
             case .retrieveTaxBasedOnSetting(_, let onCompletion):
@@ -2423,7 +2437,8 @@ final class EditableOrderViewModelTests: XCTestCase {
         let viewModel = EditableOrderViewModel(siteID: sampleSiteID,
                                                stores: stores)
 
-        XCTAssertEqual(viewModel.paymentDataViewModel.taxBasedOnSetting?.displayString, NSLocalizedString("Calculated on shipping address.", comment: ""))
+        // Then
+        XCTAssertEqual(viewModel.paymentDataViewModel.taxBasedOnSetting?.displayTaxCalculationHint, expectedString)
     }
 
     func test_payment_data_view_model_when_calling_onDismissWpAdminWebViewClosure_then_calls_to_update_elements() {