1. Turn on concurrency debug. 2. Fix unit tests.

Author: tapashmajumder

swift-sdk.xcodeproj/xcshareddata/xcschemes/swift-sdk.xcscheme

@@ -183,6 +183,12 @@
             ReferencedContainer = "container:swift-sdk.xcodeproj">
          </BuildableReference>
       </BuildableProductRunnable>
+      <CommandLineArguments>
+         <CommandLineArgument
+            argument = "-com.apple.CoreData.ConcurrencyDebug 1"
+            isEnabled = "YES">
+         </CommandLineArgument>
+      </CommandLineArguments>
    </LaunchAction>
    <ProfileAction
       buildConfiguration = "Release"

tests/common/CommonMocks.swift

@@ -202,6 +202,7 @@ class MockNetworkSession: NetworkSessionProtocol {
     }
 
     var responseCallback: ((URL) -> MockResponse?)?
+    var queue: DispatchQueue
 
     var timeout: TimeInterval = 60.0
 
@@ -238,8 +239,10 @@ class MockNetworkSession: NetworkSessionProtocol {
         self.init(responseCallback: responseCallback)
     }
 
-    init(responseCallback: ((URL) -> MockResponse?)?) {
+    init(responseCallback: ((URL) -> MockResponse?)?,
+         queue: DispatchQueue = DispatchQueue.main) {
         self.responseCallback = responseCallback
+        self.queue = queue
     }
 
     func makeRequest(_ request: URLRequest, completionHandler: @escaping NetworkSessionProtocol.CompletionHandler) {
@@ -261,16 +264,16 @@ class MockNetworkSession: NetworkSessionProtocol {
 
         let delay = mockResponse?.delay ?? 0
         if  delay == 0 {
-            DispatchQueue.main.async {
+            queue.async {
                 block()
             }
         } else {
             if delay < timeout {
-                DispatchQueue.main.asyncAfter(deadline: .now() + delay) {
+                queue.asyncAfter(deadline: .now() + delay) {
                     block()
                 }
             } else {
-                DispatchQueue.main.asyncAfter(deadline: .now() + timeout) {
+                queue.asyncAfter(deadline: .now() + timeout) {
                     let error = NetworkError(reason: "The request timed out.")
                     completionHandler(nil, nil, error)
                     self.callback?(nil, nil, error)
@@ -299,11 +302,11 @@ class MockNetworkSession: NetworkSessionProtocol {
 
         let delay = mockResponse?.delay ?? 0
         if delay == 0 {
-            DispatchQueue.main.async {
+            queue.async {
                 block()
             }
         } else {
-            DispatchQueue.main.asyncAfter(deadline: .now() + delay) {
+            queue.asyncAfter(deadline: .now() + delay) {
                 block()
             }
         }

tests/offline-events-tests/HealthMonitorTests.swift

@@ -47,15 +47,18 @@ class HealthMonitorTests: XCTestCase {
 
     func testSwitchProcessorsWhenNumTasksExceedsMaxTasks() throws {
         let expectation1 = expectation(description: #function)
-        expectation1.expectedFulfillmentCount = 3
         let networkSession = MockNetworkSession(statusCode: 200)
+        networkSession.queue = DispatchQueue.global(qos: .userInitiated)
         var processorMap = [String: String]()
         networkSession.requestCallback = { request in
             if request.url!.absoluteString.contains(Const.Path.trackEvent) {
                 let eventName = request.bodyDict["eventName"] as! String
-                let processor = request.allHTTPHeaderFields?[JsonKey.Header.requestProcessor]!
-                processorMap[eventName] = processor!
-                expectation1.fulfill()
+                let processor = (request.allHTTPHeaderFields?[JsonKey.Header.requestProcessor]!)!
+                processorMap[eventName] = processor
+                
+                if eventName == "myEvent", processor == "Offline" {
+                    expectation1.fulfill()
+                }
             }
         }
         let localStorage = MockLocalStorage()
@@ -66,15 +69,30 @@ class HealthMonitorTests: XCTestCase {
                                                                    maxTasks: 1)
 
         internalAPI.track("myEvent")
-        internalAPI.track("myEvent2").onSuccess { _ in
-            DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) {
-                internalAPI.track("myEvent3")
+        
+        wait(for: [expectation1], timeout: testExpectationTimeout)
+
+        let changedToOnline = TestUtils.tryUntil(attempts: 10) {
+            internalAPI.track("myEvent2")
+        } test: {
+            if let value = processorMap["myEvent2"], value == "Online" {
+                return true
+            } else {
+                return false
             }
         }
-        wait(for: [expectation1], timeout: testExpectationTimeout)
-        XCTAssertEqual(processorMap["myEvent"], "Offline")
-        XCTAssertEqual(processorMap["myEvent2"], "Online")
-        XCTAssertEqual(processorMap["myEvent3"], "Offline")
+        XCTAssertTrue(changedToOnline)
+
+        let changedBackToOffline = TestUtils.tryUntil(attempts: 10) {
+            internalAPI.track("myEvent3")
+        } test: {
+            if let value = processorMap["myEvent3"], value == "Offline" {
+                return true
+            } else {
+                return false
+            }
+        }
+        XCTAssertTrue(changedBackToOffline)
     }
 
     func testCountTasksException() throws {