fix: Fix cancellation logic for AWSGraphQLSubscriptionOperation (#650)

Author: palpatim

AmplifyPlugins/API/APICategoryPlugin.xcodeproj/project.pbxproj

@@ -132,6 +132,7 @@
 		B4DFA5F9237A611D0013E17B /* AWSAPICategoryPlugin+URLSessionDelegateTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = B4DFA5DF237A611D0013E17B /* AWSAPICategoryPlugin+URLSessionDelegateTests.swift */; };
 		FA8EE785238632620097E4F1 /* AWSAPIPlugin+Log.swift in Sources */ = {isa = PBXBuildFile; fileRef = FA8EE784238632620097E4F1 /* AWSAPIPlugin+Log.swift */; };
 		FA97F5532386CCF500EE9EFE /* AnyModelIntegrationTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = FA97F5522386CCF500EE9EFE /* AnyModelIntegrationTests.swift */; };
+		FAA7A5AA24C0E01500CA863F /* AWSGraphQLSubscriptionOperationCancelTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = FAA7A5A924C0E01500CA863F /* AWSGraphQLSubscriptionOperationCancelTests.swift */; };
 		FAC5F9B1238B70EE00F70F02 /* APICategoryPluginConcurrencyTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = FA9554DF238B6C0B00D42A43 /* APICategoryPluginConcurrencyTests.swift */; };
 /* End PBXBuildFile section */
 
@@ -443,6 +444,7 @@
 		FA8EE784238632620097E4F1 /* AWSAPIPlugin+Log.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "AWSAPIPlugin+Log.swift"; sourceTree = "<group>"; };
 		FA9554DF238B6C0B00D42A43 /* APICategoryPluginConcurrencyTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = APICategoryPluginConcurrencyTests.swift; sourceTree = "<group>"; };
 		FA97F5522386CCF500EE9EFE /* AnyModelIntegrationTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AnyModelIntegrationTests.swift; sourceTree = "<group>"; };
+		FAA7A5A924C0E01500CA863F /* AWSGraphQLSubscriptionOperationCancelTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AWSGraphQLSubscriptionOperationCancelTests.swift; sourceTree = "<group>"; };
 		FC6404420A9C03FAB55FA8B3 /* Pods-AWSAPICategoryPluginGraphQLAPIKeyIntegrationTests.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-AWSAPICategoryPluginGraphQLAPIKeyIntegrationTests.debug.xcconfig"; path = "Target Support Files/Pods-AWSAPICategoryPluginGraphQLAPIKeyIntegrationTests/Pods-AWSAPICategoryPluginGraphQLAPIKeyIntegrationTests.debug.xcconfig"; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
@@ -931,7 +933,7 @@
 				B4DFA5D5237A611D0013E17B /* AWSAPICategoryPlugin+URLSessionBehaviorDelegateTests.swift */,
 				B4DFA5DF237A611D0013E17B /* AWSAPICategoryPlugin+URLSessionDelegateTests.swift */,
 				B4DFA5CB237A611D0013E17B /* AWSAPICategoryPluginTestBase.swift */,
-				FA9554E1238B6C1200D42A43 /* Concurrency */,
+				FAA7A5A924C0E01500CA863F /* AWSGraphQLSubscriptionOperationCancelTests.swift */,
 				B4DFA5C6237A611D0013E17B /* Configuration */,
 				B4DFA5D9237A611D0013E17B /* Interceptor */,
 				B4DFA5BF237A611D0013E17B /* Mocks */,
@@ -1064,13 +1066,6 @@
 			path = Pods;
 			sourceTree = "<group>";
 		};
-		FA9554E1238B6C1200D42A43 /* Concurrency */ = {
-			isa = PBXGroup;
-			children = (
-			);
-			path = Concurrency;
-			sourceTree = "<group>";
-		};
 		FA99642D246EF8B40020E879 /* Resources */ = {
 			isa = PBXGroup;
 			children = (
@@ -2195,6 +2190,7 @@
 				B4DFA5E0237A611D0013E17B /* MockSessionFactory.swift in Sources */,
 				6B2E465A23AAA6AF0066EDCE /* NetworkReachabilityNotifierTests.swift in Sources */,
 				B4DFA5E1237A611D0013E17B /* MockURLSessionTask.swift in Sources */,
+				FAA7A5AA24C0E01500CA863F /* AWSGraphQLSubscriptionOperationCancelTests.swift in Sources */,
 				B4DFA5F8237A611D0013E17B /* AWSAPICategoryPlugin+ConfigureTests.swift in Sources */,
 				21E2E22A2451E6B5007D7767 /* GraphQLResponseDecoderDecodeErrorTests.swift in Sources */,
 				B4DFA5F1237A611D0013E17B /* AWSAPICategoryPlugin+URLSessionBehaviorDelegateTests.swift in Sources */,

AmplifyPlugins/API/AWSAPICategoryPlugin/Operation/AWSGraphQLSubscriptionOperation.swift

@@ -43,11 +43,10 @@ final public class AWSGraphQLSubscriptionOperation<R: Decodable>: GraphQLSubscri
             subscriptionConnection.unsubscribe(item: subscriptionItem)
             let subscriptionEvent = SubscriptionEvent<GraphQLResponse<R>>.connection(.disconnected)
             dispatchInProcess(data: subscriptionEvent)
-            dispatch(result: .successfulVoid)
-            finish()
-        } else {
-            super.cancel()
         }
+        super.cancel()
+        dispatch(result: .successfulVoid)
+        finish()
     }
 
     override public func main() {

AmplifyPlugins/API/AWSAPICategoryPluginTests/AWSGraphQLSubscriptionOperationCancelTests.swift

@@ -0,0 +1,55 @@
+//
+// Copyright 2018-2020 Amazon.com,
+// Inc. or its affiliates. All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import XCTest
+
+@testable import Amplify
+@testable import AWSAPICategoryPlugin
+@testable import AmplifyTestCommon
+
+// swiftlint:disable:next type_name
+class AWSGraphQLSubscriptionOperationCancelTests: AWSAPICategoryPluginTestBase {
+
+    func testCancelSendsCompletion() {
+        let request = GraphQLRequest(apiName: apiName,
+                                     document: testDocument,
+                                     variables: nil,
+                                     responseType: JSONValue.self)
+
+        let receivedCompletion = expectation(description: "Received completion")
+        let receivedFailure = expectation(description: "Received failure")
+        receivedFailure.isInverted = true
+        let receivedValue = expectation(description: "Received value")
+        receivedValue.isInverted = true
+
+        let valueListener: GraphQLSubscriptionOperation<JSONValue>.InProcessListener = { _ in
+            receivedValue.fulfill()
+        }
+
+        let completionListener: GraphQLSubscriptionOperation<JSONValue>.ResultListener = { result in
+            switch result {
+            case .failure:
+                receivedFailure.fulfill()
+            case .success:
+                receivedCompletion.fulfill()
+            }
+        }
+
+        let operation = apiPlugin.subscribe(
+            request: request,
+            valueListener: valueListener,
+            completionListener: completionListener
+        )
+
+        operation.cancel()
+
+        XCTAssert(operation.isCancelled)
+
+        waitForExpectations(timeout: 0.05)
+    }
+
+}