From 6a735daf416d0f0c575b547468d4d7026553dc06 Mon Sep 17 00:00:00 2001
From: Marco Betschart <marco@mandelkind.swiss>
Date: Sat, 17 Mar 2018 13:12:03 +0100
Subject: [PATCH] Decimal Arithmetics

Added support for arithmetic operations using Decimals
---
 Sources/MoneyProtocol.swift     | 35 +++++++++++++++++++++++++++++++++
 Tests/AdditionTests.swift       | 16 +++++++++++++++
 Tests/DivisionTests.swift       | 16 +++++++++++++++
 Tests/MultiplicationTests.swift | 16 +++++++++++++++
 4 files changed, 83 insertions(+)

diff --git a/Sources/MoneyProtocol.swift b/Sources/MoneyProtocol.swift
index 08e8f10..0d59d29 100644
--- a/Sources/MoneyProtocol.swift
+++ b/Sources/MoneyProtocol.swift
@@ -151,6 +151,41 @@ extension MoneyProtocol where FloatLiteralType == Decimal.FloatLiteralType {
     }
 }
 
+extension MoneyProtocol {
+	
+	public static func +(lhs: Self, rhs: Decimal) -> Self {
+		return Self(decimal: lhs.decimal + rhs)
+	}
+	
+	public static func +(lhs: Decimal, rhs: Self) -> Self {
+		return Self(decimal: lhs + rhs.decimal)
+	}
+	
+	public static func -(lhs: Self, rhs: Decimal) -> Self {
+		return Self(decimal: lhs.decimal - rhs)
+	}
+	
+	public static func -(lhs: Decimal, rhs: Self) -> Self {
+		return Self(decimal: lhs - rhs.decimal)
+	}
+	
+	public static func *(lhs: Self, rhs: Decimal) -> Self {
+		return Self(decimal: lhs.decimal * rhs)
+	}
+	
+	public static func *(lhs: Decimal, rhs: Self) -> Self {
+		return Self(decimal: lhs * rhs.decimal)
+	}
+	
+	public static func /(lhs: Self, rhs: Decimal) -> Self {
+		return Self(decimal: lhs.decimal / rhs)
+	}
+	
+	public static func /(lhs: Decimal, rhs: Self) -> Self {
+		return Self(decimal: lhs / rhs.decimal)
+	}
+}
+
 public extension MoneyProtocol {
 
     func distance(to other: Self) -> Self {
diff --git a/Tests/AdditionTests.swift b/Tests/AdditionTests.swift
index c469693..47e182d 100644
--- a/Tests/AdditionTests.swift
+++ b/Tests/AdditionTests.swift
@@ -31,6 +31,14 @@ extension MoneyTestCase {
         let result = 3.5 + money + 2.5
         XCTAssertEqual(result, 16)
     }
+	
+	func test__money_addition_by_decimals() {
+		money = 10
+		let a: Decimal = 3.5
+		let b: Decimal = 2.5
+		let result = a + money + b
+		XCTAssertEqual(result, 16)
+	}
 }
 
 extension MoneyTestCase {
@@ -52,4 +60,12 @@ extension MoneyTestCase {
         let result = 3.5 + gbp + 2.5
         XCTAssertEqual(result, 16)
     }
+	
+	func test__iso_addition_by_decimals() {
+		gbp = 10
+		let a: Decimal = 3.5
+		let b: Decimal = 2.5
+		let result = a + gbp + b
+		XCTAssertEqual(result, 16)
+	}
 }
diff --git a/Tests/DivisionTests.swift b/Tests/DivisionTests.swift
index de08824..1ecb8d8 100644
--- a/Tests/DivisionTests.swift
+++ b/Tests/DivisionTests.swift
@@ -31,6 +31,14 @@ extension MoneyTestCase {
         let result = 3.5 / money / 2.5
         XCTAssertEqual(result.floatValue, 0.14, accuracy: 0.001)
     }
+	
+	func test__money_division_by_decimals() {
+		money = 10
+		let a: Decimal = 3.5
+		let b: Decimal = 2.5
+		let result = a / money / b
+		XCTAssertEqual(result.floatValue, 0.14, accuracy: 0.001)
+	}
 }
 
 extension MoneyTestCase {
@@ -52,6 +60,14 @@ extension MoneyTestCase {
         let result = 3.5 / gbp / 2.5
         XCTAssertEqual(result.floatValue, 0.14, accuracy: 0.001)
     }
+	
+	func test__iso_division_by_decimals() {
+		gbp = 10
+		let a: Decimal = 3.5
+		let b: Decimal = 2.5
+		let result = a / gbp / b
+		XCTAssertEqual(result.floatValue, 0.14, accuracy: 0.001)
+	}
 }
 
 
diff --git a/Tests/MultiplicationTests.swift b/Tests/MultiplicationTests.swift
index 11b0d4d..b582ec6 100644
--- a/Tests/MultiplicationTests.swift
+++ b/Tests/MultiplicationTests.swift
@@ -31,6 +31,14 @@ extension MoneyTestCase {
         let result = 3.5 * money * 2.5
         XCTAssertEqual(result, 87.5)
     }
+	
+	func test__money_multiplation_by_decimals() {
+		money = 10
+		let a: Decimal = 3.5
+		let b: Decimal = 2.5
+		let result = a * money * b
+		XCTAssertEqual(result, 87.5)
+	}
 }
 
 extension MoneyTestCase {
@@ -52,4 +60,12 @@ extension MoneyTestCase {
         let result = 3.5 * gbp * 2.5
         XCTAssertEqual(result, 87.5)
     }
+	
+	func test__iso_multiplation_by_decimals() {
+		gbp = 10
+		let a: Decimal = 3.5
+		let b: Decimal = 2.5
+		let result = a * gbp * b
+		XCTAssertEqual(result, 87.5)
+	}
 }