suggestedFilename always returns a valid filename

Sources/FoundationNetworking/URLResponse.swift

@@ -46,8 +46,11 @@ open class URLResponse : NSObject, NSSecureCoding, NSCopying {
             self.textEncodingName = encodedEncodingName as String
         }
 
-        if let encodedFilename = aDecoder.decodeObject(of: NSString.self, forKey: "NS.suggestedFilename") {
-            self.suggestedFilename = encodedFilename as String
+        if let encodedFilename = aDecoder.decodeObject(of: NSString.self, forKey: "NS.suggestedFilename")?.lastPathComponent,
+           !encodedFilename.isEmpty {
+            self.suggestedFilename = encodedFilename
+        } else {
+            self.suggestedFilename = "Unknown"
         }
     }
 

Tests/Foundation/Tests/TestURLResponse.swift

@@ -81,7 +81,7 @@ class TestURLResponse : XCTestCase {
     func test_NSCoding() {
         let url = URL(string: "https://apple.com")!
         let responseA = URLResponse(url: url, mimeType: "txt", expectedContentLength: 0, textEncodingName: nil)
-        let responseB = NSKeyedUnarchiver.unarchiveObject(with: NSKeyedArchiver.archivedData(withRootObject: responseA)) as! URLResponse
+        let responseB = try! NSKeyedUnarchiver.unarchivedObject(ofClass: URLResponse.self, from: NSKeyedArchiver.archivedData(withRootObject: responseA))!
 
         //On macOS unarchived Archived then unarchived `URLResponse` is not equal.
         XCTAssertEqual(responseA.url, responseB.url, "Archived then unarchived url response must be equal.")
@@ -91,6 +91,46 @@ class TestURLResponse : XCTestCase {
         XCTAssertEqual(responseA.suggestedFilename, responseB.suggestedFilename, "Archived then unarchived url response must be equal.")
     }
 
+    func test_NSCodingEmptySuggestedFilename() {
+        let url = URL(string: "https://apple.com")!
+        let responseA = URLResponse(url: url, mimeType: "txt", expectedContentLength: 0, textEncodingName: nil)
+
+        // archiving in xml format
+        let archiver = NSKeyedArchiver(requiringSecureCoding: false)
+        archiver.outputFormat = .xml
+        archiver.encode(responseA, forKey: NSKeyedArchiveRootObjectKey)
+        var plist = String(data: archiver.encodedData, encoding: .utf8)!
+
+        // clearing the filename in the archive
+        plist = plist.replacingOccurrences(of: "Unknown", with: "")
+        let data = plist.data(using: .utf8)!
+
+        // unarchiving
+        let responseB = try! NSKeyedUnarchiver.unarchivedObject(ofClass: URLResponse.self, from: data)!
+
+        XCTAssertEqual(responseB.suggestedFilename, "Unknown", "Unarchived filename must be valid.")
+    }
+
+    func test_NSCodingInvalidSuggestedFilename() {
+        let url = URL(string: "https://apple.com")!
+        let responseA = URLResponse(url: url, mimeType: "txt", expectedContentLength: 0, textEncodingName: nil)
+
+        // archiving in xml format
+        let archiver = NSKeyedArchiver(requiringSecureCoding: false)
+        archiver.outputFormat = .xml
+        archiver.encode(responseA, forKey: NSKeyedArchiveRootObjectKey)
+        var plist = String(data: archiver.encodedData, encoding: .utf8)!
+
+        // invalidating the filename in the archive
+        plist = plist.replacingOccurrences(of: "Unknown", with: "invalid/valid")
+        let data = plist.data(using: .utf8)!
+
+        // unarchiving
+        let responseB = try! NSKeyedUnarchiver.unarchivedObject(ofClass: URLResponse.self, from: data)!
+
+        XCTAssertEqual(responseB.suggestedFilename, "valid", "Unarchived filename must be valid.")
+    }
+
     func test_equalWithTheSameInstance() throws {
         let url = try XCTUnwrap(URL(string: "http://example.com/"))
         let response = URLResponse(url: url, mimeType: nil, expectedContentLength: -1, textEncodingName: nil)
@@ -188,6 +228,8 @@ class TestURLResponse : XCTestCase {
             ("test_suggestedFilename_3", test_suggestedFilename_3),
             ("test_copywithzone", test_copyWithZone),
             ("test_NSCoding", test_NSCoding),
+            ("test_NSCodingEmptySuggestedFilename", test_NSCodingEmptySuggestedFilename),
+            ("test_NSCodingInvalidSuggestedFilename", test_NSCodingInvalidSuggestedFilename),
             ("test_equalWithTheSameInstance", test_equalWithTheSameInstance),
             ("test_equalWithUnrelatedObject", test_equalWithUnrelatedObject),
             ("test_equalCheckingURL", test_equalCheckingURL),