Fix access level for init and other tweaks

Fixes #6

Sources/Defaults/Defaults.swift

@@ -1,14 +1,16 @@
 // MIT License © Sindre Sorhus
-import Cocoa
+import Foundation
 
 public final class Defaults {
-	public class Keys {}
+	public class Keys {
+		fileprivate init() {}
+	}
 
 	public final class Key<T: Codable>: Keys {
 		fileprivate let name: String
 		fileprivate let defaultValue: T
 
-		init(_ key: String, default defaultValue: T) {
+		public init(_ key: String, default defaultValue: T) {
 			self.name = key
 			self.defaultValue = defaultValue
 		}
@@ -17,7 +19,7 @@ public final class Defaults {
 	public final class OptionalKey<T: Codable>: Keys {
 		fileprivate let name: String
 
-		init(_ key: String) {
+		public init(_ key: String) {
 			self.name = key
 		}
 	}

Tests/DefaultsTests/DefaultsTests.swift

@@ -1,5 +1,5 @@
 import XCTest
-@testable import Defaults
+import Defaults
 
 let fixtureUrl = URL(string: "httos://sindresorhus.com")!
 
@@ -22,7 +22,7 @@ final class DefaultsTests: XCTestCase {
 		defaults.clear()
 	}
 
-    func testKey() {
+	func testKey() {
 		let key = Defaults.Key<Bool>("key", default: false)
 		XCTAssertFalse(UserDefaults.standard[key])
 		UserDefaults.standard[key] = true