Several NSString constructors implemented

Foundation/NSString.swift

@@ -694,11 +694,13 @@ extension NSString {
     }
 
     public convenience init?(data: NSData, encoding: UInt) {
-        NSUnimplemented()    
+        self.init(bytes: data.bytes, length: data.length, encoding: encoding)
     }
 
     public convenience init?(bytes: UnsafePointer<Void>, length len: Int, encoding: UInt) {
-        let cf = CFStringCreateWithBytes(kCFAllocatorDefault, UnsafePointer<UInt8>(bytes), len, CFStringConvertNSStringEncodingToEncoding(encoding), true)
+        guard let cf = CFStringCreateWithBytes(kCFAllocatorDefault, UnsafePointer<UInt8>(bytes), len, CFStringConvertNSStringEncodingToEncoding(encoding), true) else {
+            return nil
+        }
         self.init(cf._swiftObject)
     }
 
@@ -707,7 +709,10 @@ extension NSString {
     }
 
     public convenience init?(CString nullTerminatedCString: UnsafePointer<Int8>, encoding: UInt) {
-        NSUnimplemented()    
+        guard let cf = CFStringCreateWithCString(kCFAllocatorDefault, nullTerminatedCString, CFStringConvertNSStringEncodingToEncoding(encoding)) else {
+            return nil
+        }
+        self.init(cf._swiftObject)
     }
 
     public convenience init(contentsOfURL url: NSURL, encoding enc: UInt) throws {

TestFoundation/TestNSString.swift

@@ -22,6 +22,16 @@ class TestNSString : XCTestCase {
     var allTests : [(String, () -> ())] {
         return [
             ("test_BridgeConstruction", test_BridgeConstruction ),
+            ("test_isEqualToStringWithSwiftString", test_isEqualToStringWithSwiftString ),
+            ("test_FromASCIIData", test_FromASCIIData ),
+            ("test_FromUTF8Data", test_FromUTF8Data ),
+            ("test_FromMalformedUTF8Data", test_FromMalformedUTF8Data ),
+            ("test_FromASCIINSData", test_FromASCIINSData ),
+            ("test_FromUTF8NSData", test_FromUTF8NSData ),
+            ("test_FromMalformedUTF8NSData", test_FromMalformedUTF8NSData ),
+            ("test_FromNullTerminatedCStringInASCII", test_FromNullTerminatedCStringInASCII ),
+            ("test_FromNullTerminatedCStringInUTF8", test_FromNullTerminatedCStringInUTF8 ),
+            ("test_FromMalformedNullTerminatedCStringInUTF8", test_FromMalformedNullTerminatedCStringInUTF8 ),
         ]
     }
 
@@ -42,4 +52,79 @@ class TestNSString : XCTestCase {
         let cluster: NSString = "✌🏾"
         XCTAssertEqual(cluster.length, 3)
     }
+
+    func test_isEqualToStringWithSwiftString() {
+        let string: NSString = "literal"
+        let swiftString = "literal"
+        XCTAssertTrue(string.isEqualToString(swiftString))
+    }
+
+    internal let mockASCIIStringBytes: [UInt8] = [0x48, 0x65, 0x6C, 0x6C, 0x6F, 0x20, 0x53, 0x77, 0x69, 0x66, 0x74, 0x21]
+    internal let mockASCIIString = "Hello Swift!"
+    internal let mockUTF8StringBytes: [UInt8] = [0x49, 0x20, 0xE2, 0x9D, 0xA4, 0xEF, 0xB8, 0x8F, 0x20, 0x53, 0x77, 0x69, 0x66, 0x74]
+    internal let mockUTF8String = "I ❤️ Swift"
+    internal let mockMalformedUTF8StringBytes: [UInt8] = [0xFF]
+
+    func test_FromASCIIData() {
+        let bytes = mockASCIIStringBytes
+        let string = NSString(bytes: bytes, length: bytes.count, encoding: NSASCIIStringEncoding)
+        XCTAssertNotNil(string)
+        XCTAssertTrue(string?.isEqualToString(mockASCIIString) ?? false)
+    }
+
+    func test_FromUTF8Data() {
+        let bytes = mockUTF8StringBytes
+        let string = NSString(bytes: bytes, length: bytes.count, encoding: NSUTF8StringEncoding)
+        XCTAssertNotNil(string)
+        XCTAssertTrue(string?.isEqualToString(mockUTF8String) ?? false)
+    }
+
+    func test_FromMalformedUTF8Data() {
+        let bytes = mockMalformedUTF8StringBytes
+        let string = NSString(bytes: bytes, length: bytes.count, encoding: NSUTF8StringEncoding)
+        XCTAssertNil(string)
+    }
+
+    func test_FromASCIINSData() {
+        let bytes = mockASCIIStringBytes
+        let data = NSData(bytes: bytes, length: bytes.count)
+        let string = NSString(data: data, encoding: NSASCIIStringEncoding)
+        XCTAssertNotNil(string)
+        XCTAssertTrue(string?.isEqualToString(mockASCIIString) ?? false)
+    }
+
+    func test_FromUTF8NSData() {
+        let bytes = mockUTF8StringBytes
+        let data = NSData(bytes: bytes, length: bytes.count)
+        let string = NSString(data: data, encoding: NSUTF8StringEncoding)
+        XCTAssertNotNil(string)
+        XCTAssertTrue(string?.isEqualToString(mockUTF8String) ?? false)
+    }
+
+    func test_FromMalformedUTF8NSData() {
+        let bytes = mockMalformedUTF8StringBytes
+        let data = NSData(bytes: bytes, length: bytes.count)
+        let string = NSString(data: data, encoding: NSUTF8StringEncoding)
+        XCTAssertNil(string)
+    }
+
+    func test_FromNullTerminatedCStringInASCII() {
+        let bytes = mockASCIIStringBytes + [0x00]
+        let string = NSString(CString: bytes.map { Int8(bitPattern: $0) }, encoding: NSASCIIStringEncoding)
+        XCTAssertNotNil(string)
+        XCTAssertTrue(string?.isEqualToString(mockASCIIString) ?? false)
+    }
+
+    func test_FromNullTerminatedCStringInUTF8() {
+        let bytes = mockUTF8StringBytes + [0x00]
+        let string = NSString(CString: bytes.map { Int8(bitPattern: $0) }, encoding: NSUTF8StringEncoding)
+        XCTAssertNotNil(string)
+        XCTAssertTrue(string?.isEqualToString(mockUTF8String) ?? false)
+    }
+
+    func test_FromMalformedNullTerminatedCStringInUTF8() {
+        let bytes = mockMalformedUTF8StringBytes + [0x00]
+        let string = NSString(CString: bytes.map { Int8(bitPattern: $0) }, encoding: NSUTF8StringEncoding)
+        XCTAssertNil(string)
+    }
 }