Distribute the size evenly between short orders

 - Update unit tests.

Author: backslash-f

Sources/SwiftTrader/BusinessLogic/MultiOrders/SwiftTrader+MultipleShortLimitOrders.swift

@@ -45,7 +45,8 @@ public extension SwiftTrader {
             formattedPrices.insert(formattedPrice)
             previousPrice = price
 
-            let formattedSize = formatSize(orderInput.totalSize, decimalPlaces: decimalPlaces)
+            let sizePerOrder = orderInput.totalSize / numberOfOrders
+            let formattedSize = formatSize(sizePerOrder, decimalPlaces: decimalPlaces)
 
             let order = KucoinSpotHFOrderParameters(
                 symbol: orderInput.symbol,

Sources/SwiftTrader/Model/Kucoin/Order/HF/KucoinSpotHFShortLimitOrdersResult.swift

@@ -21,7 +21,13 @@ public struct KucoinSpotHFShortLimitOrdersResult: Equatable, Codable {
         orders.map { $0.price }
     }
 
+    /// An array of the sizes of the submitted orders.
     public var sizes: [String] {
         orders.map { $0.size }
     }
+
+    /// The total size of all the submitted orders.
+    public var totalSize: Double {
+        orders.compactMap { Double($0.size) }.reduce(0, +)
+    }
 }

Sources/SwiftTrader/Model/MultiOrders/SwiftTraderMultiShortLimitOrderInput.swift

@@ -34,8 +34,8 @@ public struct SwiftTraderMultiShortLimitOrderInput {
     ///   - priceDecrement: How much the price of subsequent orders (second, third, fourth, and fifth)
     ///   should go **down**.
     ///   The value indicates the percentage. For example: 0,1 = 10%.
-    ///   - totalSize: The total size of the acquired asset. Each created order will use this number as its size.
-    ///  This way, all available assets will be sold once one of the five orders is filled, maximazing the profit.
+    ///   - totalSize: The total size available for the operation. The number will be distributed evenly
+    ///   between all submitted orders.
     public init(symbol: String,
                 initialPrice: String,
                 targetProfitPercentage: Double,

Tests/SwiftTraderTests/CreateMultiShortLimitOrderTests.swift

@@ -74,10 +74,21 @@ final class CreateMultiShortLimitOrderTests: XCTestCase {
             for (index, order) in result.enumerated() {
                 XCTAssertEqual(
                     order.size,
-                    testCase.expectedSize,
-                    "Order \(index + 1) size should be \(testCase.expectedSize)"
+                    testCase.expectedSizes[index],
+                    "Order \(index + 1) size should be \(testCase.expectedSizes[index])"
                 )
             }
+
+            let totalExpectedSize = testCase.expectedSizes.compactMap { Double($0) }.reduce(0, +)
+            let totalSize = testCase.input.totalSize
+
+            XCTAssertTrue(
+                totalExpectedSize <= totalSize,
+                """
+                    The expected size should be less then/equal to the total size \(totalSize)
+                    -- and not \(totalExpectedSize)
+                """
+            )
         }
     }
 }
@@ -147,7 +158,13 @@ private extension CreateMultiShortLimitOrderTests {
                     "0.6874",
                     "0.6806"
                 ],
-                expectedSize: "92"
+                expectedSizes: [
+                    "18",
+                    "18",
+                    "18",
+                    "18",
+                    "18"
+                ]
             ),
 
             TestCase(
@@ -159,7 +176,13 @@ private extension CreateMultiShortLimitOrderTests {
                     "0.00000178",
                     "0.00000177"
                 ],
-                expectedSize: "70485494"
+                expectedSizes: [
+                    "14097098",
+                    "14097098",
+                    "14097098",
+                    "14097098",
+                    "14097098"
+                ]
             ),
 
             TestCase(
@@ -171,7 +194,13 @@ private extension CreateMultiShortLimitOrderTests {
                     "308.85",
                     "305.76"
                 ],
-                expectedSize: "0.60"
+                expectedSizes: [
+                    "0.12",
+                    "0.12",
+                    "0.12",
+                    "0.12",
+                    "0.12"
+                ]
             ),
 
             TestCase(
@@ -183,7 +212,13 @@ private extension CreateMultiShortLimitOrderTests {
                     "1.75",
                     "1.73"
                 ],
-                expectedSize: "136"
+                expectedSizes: [
+                    "27",
+                    "27",
+                    "27",
+                    "27",
+                    "27"
+                ]
             ),
 
             TestCase(
@@ -195,14 +230,20 @@ private extension CreateMultiShortLimitOrderTests {
                     "0.073",
                     "0.072"
                 ],
-                expectedSize: "4333"
+                expectedSizes: [
+                    "866",
+                    "866",
+                    "866",
+                    "866",
+                    "866"
+                ]
             )
         ]
     }
 
     struct TestCase {
         let input: SwiftTraderMultiShortLimitOrderInput
         let expectedPrices: [String]
-        let expectedSize: String
+        let expectedSizes: [String]
     }
 }