Implementation of URLSessionTask '.error', NSCopying

Docs/Status.md

@@ -78,7 +78,7 @@ There is no _Complete_ status for test coverage because there are always additio
     | `URLSession`                 | Mostly Complete | Incomplete    | `shared`, invalidation, resetting, flushing, getting tasks, and others remain unimplemented                        |
     | `URLSessionConfiguration`    | Mostly Complete | Incomplete    | `ephemeral` and `background(withIdentifier:)` remain unimplemented                                                 |
     | `URLSessionDelegate`         | Complete        | N/A           |                                                                                                                    |
-    | `URLSessionTask`             | Mostly Complete | Incomplete    | `NSCopying`, `cancel()`, `error`, `createTransferState(url:)` with streams, and others remain unimplemented        |
+    | `URLSessionTask`             | Mostly Complete | Incomplete    | `cancel()`, `createTransferState(url:)` with streams, and others remain unimplemented                              |
     | `URLSessionDataTask`         | Complete        | Incomplete    |                                                                                                                    |
     | `URLSessionUploadTask`       | Complete        | None          |                                                                                                                    |
     | `URLSessionDownloadTask`     | Incomplete      | Incomplete    | `cancel(byProducingResumeData:)` remains unimplemented                                                             |

Foundation/NSURLSession/NSURLSessionTask.swift

@@ -128,7 +128,7 @@ open class URLSessionTask : NSObject, NSCopying {
     }
 
     open func copy(with zone: NSZone?) -> Any {
-        NSUnimplemented()
+        return self
     }
 
     /// An identifier for this task, assigned by and unique to the owning session
@@ -221,7 +221,10 @@ open class URLSessionTask : NSObject, NSCopying {
      * The error, if any, delivered via -URLSession:task:didCompleteWithError:
      * This property will be nil in the event that no error occured.
      */
-    /*@NSCopying*/ open var error: NSError? { NSUnimplemented() }
+    fileprivate var _error: NSError?
+    /*@NSCopying*/ open var error: NSError? {
+        return self._error
+    }
 
     /// Suspend the task.
     ///
@@ -877,6 +880,8 @@ extension URLSessionTask {
         }
     }
     func completeTask(withError error: NSError) {
+        self._error = error
+
         guard case .transferFailed = internalState else {
             fatalError("Trying to complete the task, but its transfer isn't complete / failed.")
         }
@@ -1032,8 +1037,8 @@ fileprivate extension URLSessionTask {
         guard case .waitingForResponseCompletionHandler(let ts) = internalState else { fatalError("Received response disposition, but we're not waiting for it.") }
         switch disposition {
         case .cancel:
-            //TODO: Fail the task with NSURLErrorCancelled
-            NSUnimplemented()
+            let error = NSError(domain: NSURLErrorDomain, code: NSURLErrorCancelled)
+            self.completeTask(withError: error)
         case .allow:
             // Continue the transfer. This will unpause the easy handle.
             internalState = .transferInProgress(ts)

TestFoundation/TestNSURLSession.swift

@@ -29,7 +29,9 @@ class TestURLSession : XCTestCase {
             ("test_downloadTaskWithURLRequest", test_downloadTaskWithURLRequest),
             ("test_downloadTaskWithRequestAndHandler", test_downloadTaskWithRequestAndHandler),
             ("test_downloadTaskWithURLAndHandler", test_downloadTaskWithURLAndHandler),
-            ("test_finishTaskAndInvalidate", test_finishTasksAndInvalidate)
+            ("test_finishTaskAndInvalidate", test_finishTasksAndInvalidate),
+            ("test_taskError", test_taskError),
+            ("test_taskCopy", test_taskCopy),
         ]
     }
 
@@ -262,6 +264,39 @@ class TestURLSession : XCTestCase {
         session.finishTasksAndInvalidate()
         waitForExpectations(timeout: 12)
     }
+
+    func test_taskError() {
+        let url = URL(string: "http://127.0.0.1:\(serverPort)/Nepal")!
+        let session = URLSession(configuration: URLSessionConfiguration.default,
+                                 delegate: nil,
+                                 delegateQueue: nil)
+        let completionExpectation = expectation(description: "dataTask completion block wasn't called")
+        let task = session.dataTask(with: url) { result in
+            let error = result.2
+            XCTAssertNotNil(error)
+            XCTAssertEqual(error?.code, NSURLErrorBadURL)
+            completionExpectation.fulfill()
+        }
+        //should result in Bad URL error
+        task.resume()
+
+        waitForExpectations(timeout: 5) { error in
+            XCTAssertNil(error)
+
+            XCTAssertNotNil(task.error)
+            XCTAssertEqual(task.error?.code, NSURLErrorBadURL)
+        }
+    }
+
+    func test_taskCopy() {
+        let url = URL(string: "http://127.0.0.1:\(serverPort)/Nepal")!
+        let session = URLSession(configuration: URLSessionConfiguration.default,
+                                 delegate: nil,
+                                 delegateQueue: nil)
+        let task = session.dataTask(with: url)
+
+        XCTAssert(task.isEqual(task.copy()))
+    }
 }
 
 class SessionDelegate: NSObject, URLSessionDelegate {