UnitConverter Equality fixed

Author: bubski

Foundation/Unit.swift

@@ -79,6 +79,19 @@ open class UnitConverterLinear : UnitConverter, NSSecureCoding {
     }
 
     public static var supportsSecureCoding: Bool { return true }
+
+    open override func isEqual(_ object: Any?) -> Bool {
+        guard let other = object as? UnitConverterLinear else {
+            return false
+        }
+
+        if self === other {
+            return true
+        }
+
+        return self.coefficient == other.coefficient
+            && self.constant == other.constant
+    }
 }
 
 private class UnitConverterReciprocal : UnitConverter, NSSecureCoding {
@@ -115,6 +128,18 @@ private class UnitConverterReciprocal : UnitConverter, NSSecureCoding {
     }
 
     fileprivate static var supportsSecureCoding: Bool { return true }
+
+    open override func isEqual(_ object: Any?) -> Bool {
+        guard let other = object as? UnitConverterReciprocal else {
+            return false
+        }
+
+        if self === other {
+            return true
+        }
+
+        return self.reciprocal == other.reciprocal
+    }
 }
 
 /*

TestFoundation/TestUnitConverter.swift

@@ -24,6 +24,7 @@ class TestUnitConverter: XCTestCase {
             ("test_baseUnit", test_linearity),
             ("test_linearity", test_linearity),
             ("test_bijectivity", test_bijectivity),
+            ("test_equality", test_equality),
         ]
     }
 
@@ -267,5 +268,22 @@ class TestUnitConverter: XCTestCase {
         XCTAssertEqual(testIdentity(UnitVolume.imperialGallons), 1, accuracy: delta)
         XCTAssertEqual(testIdentity(UnitVolume.metricCups), 1, accuracy: delta)
     }
+
+    func test_equality() {
+        let u1 = UnitConverterLinear(coefficient: 1, constant: 2)
+        let u2 = UnitConverterLinear(coefficient: 1, constant: 2)
+        XCTAssertEqual(u1, u2)
+        XCTAssertEqual(u2, u1)
+
+        let u3 = UnitConverterLinear(coefficient: 1, constant: 3)
+        XCTAssertNotEqual(u1, u3)
+        XCTAssertNotEqual(u3, u1)
+
+        let u4 = UnitConverterLinear(coefficient: 2, constant: 2)
+        XCTAssertNotEqual(u1, u4)
+        XCTAssertNotEqual(u4, u1)
+
+        // Cannot test UnitConverterReciprocal due to no support for @testable import.
+    }
 
 }