[MNY-79]: Fixes Mac tests

Tests/MoneyFormattingTests.swift

@@ -16,25 +16,31 @@ extension MoneyTestCase {
 
     func test__description() {
         money = 10
-        let result: String = money.formatted()
+        #if os(OSX)
+        let result: String = money.formatted(forLocaleId: "en_GB")
+        XCTAssertEqual(result, "£10")
+        #elseif os(iOS)
+        let result: String = money.formatted(forLocaleId: "en_US")
         XCTAssertEqual(result, "$10")
+        #endif
     }
 }
 
 extension MoneyTestCase {
 
     func test__iso_description() {
         gbp = 10
-        let result: String = gbp.formatted()
+        let result: String = gbp.formatted(forLocaleId: "en_GB")
         XCTAssertEqual(result, "£10.00")
     }
 
+    #if os(iOS)
     func test__iso_description_spain() {
         gbp = 10
         let result: String = gbp.formatted(forLocaleId: "es_ES")
         // Note that for Spanish from Spain, the decimal point indicator is a comma,
         // and the currency symbol is placed after the numbers.
         XCTAssertEqual(result, "10,00 £")
     }
-
+    #endif
 }