[SR-929] Implement NSString.init() with locale

Author: seabaylea

Foundation/NSString.swift

@@ -1214,7 +1214,17 @@ extension NSString {
     }
 
     public convenience init(format: String, locale: AnyObject?, arguments argList: CVaListPointer) {
-        NSUnimplemented()    
+        let str: CFString
+        if let loc = locale {
+            if loc.dynamicType === NSLocale.self || loc.dynamicType === NSDictionary.self {
+                str = CFStringCreateWithFormatAndArguments(kCFAllocatorSystemDefault, unsafeBitCast(loc, to: CFDictionary.self), format._cfObject, argList)
+            } else {
+                fatalError("locale parameter must be a NSLocale or a NSDictionary")
+            }
+        } else {
+            str = CFStringCreateWithFormatAndArguments(kCFAllocatorSystemDefault, nil, format._cfObject, argList)
+        }
+        self.init(str._swiftObject)
     }
 
     public convenience init(format: NSString, _ args: CVarArgType...) {

TestFoundation/TestNSString.swift

@@ -70,6 +70,7 @@ class TestNSString : XCTestCase {
             ("test_stringByTrimmingCharactersInSet", test_stringByTrimmingCharactersInSet),
             ("test_initializeWithFormat", test_initializeWithFormat),
             ("test_initializeWithFormat2", test_initializeWithFormat2),
+            ("test_initializeWithFormat3", test_initializeWithFormat3),
             ("test_stringByDeletingLastPathComponent", test_stringByDeletingLastPathComponent),
             ("test_getCString_simple", test_getCString_simple),
             ("test_getCString_nonASCII_withASCIIAccessor", test_getCString_nonASCII_withASCIIAccessor),
@@ -612,6 +613,35 @@ class TestNSString : XCTestCase {
         XCTAssertEqual(string, "4B")
     }
 
+    func test_initializeWithFormat3() {
+        let argument: [CVarArg] = [1000, 42.0]
+        
+        withVaList(argument) {
+            pointer in
+            let string = NSString(format: "Default value is %d (%.1f)", locale: nil, arguments: pointer)
+            XCTAssertEqual(string, "Default value is 1000 (42.0)")
+        }
+        
+        withVaList(argument) {
+            pointer in
+            let string = NSString(format: "en_GB value is %d (%.1f)", locale: NSLocale.init(localeIdentifier: "en_GB"), arguments: pointer)
+            XCTAssertEqual(string, "en_GB value is 1,000 (42.0)")
+        }
+
+        withVaList(argument) {
+            pointer in
+            let string = NSString(format: "de_DE value is %d (%.1f)", locale: NSLocale.init(localeIdentifier: "de_DE"), arguments: pointer)
+            XCTAssertEqual(string, "de_DE value is 1.000 (42,0)")
+        }
+        
+        withVaList(argument) {
+            pointer in
+            let loc: NSDictionary = ["NSDecimalSeparator" as NSString : "&" as NSString]
+            let string = NSString(format: "NSDictionary value is %d (%.1f)", locale: loc, arguments: pointer)
+            XCTAssertEqual(string, "NSDictionary value is 1000 (42&0)")
+        }
+    }
+    
     func test_stringByDeletingLastPathComponent() {
         do {
             let path: NSString = "/tmp/scratch.tiff"