test: prevent infinite loop if sdk forwards push event back to itself (…

…#516)

Sources/MessagingPush/PushHandling/PushEventHandlerProxy.swift

@@ -29,14 +29,6 @@ class PushEventHandlerProxyImpl: PushEventHandlerProxy {
     private var nestedDelegates: [String: PushEventHandler] = [:]
 
     func addPushEventHandler(_ newHandler: PushEventHandler) {
-        // this line below seems fragile. If we change the class name, this could break.
-        // could digraph inject instance of the SDK's intance before setting singleton?
-        let doesDelegateBelongToCio = newHandler is IOSPushEventListener
-
-        guard !doesDelegateBelongToCio else {
-            return
-        }
-
         nestedDelegates[String(describing: newHandler)] = newHandler
     }
 

Tests/MessagingPush/PushHandling/PushEventHandlerTest.swift

@@ -0,0 +1,41 @@
+@testable import CioMessagingPush
+import Foundation
+import SharedTests
+import XCTest
+
+class PushEventHandlerTest: UnitTest {
+    private var pushEventHandler: PushEventHandler!
+
+    private var pushEventHandlerProxy: PushEventHandlerProxy {
+        diGraph.pushEventHandlerProxy
+    }
+
+    private var pushClickHandler = PushClickHandlerMock()
+
+    override func setUp() {
+        super.setUp()
+
+        pushEventHandler = IOSPushEventListener(jsonAdapter: diGraph.jsonAdapter, pushEventHandlerProxy: pushEventHandlerProxy, moduleConfig: MessagingPushConfigOptions(), pushClickHandler: pushClickHandler, pushHistory: diGraph.pushHistory, logger: log)
+    }
+
+    // MARK: onPushAction
+
+    /*
+     The CIO SDK push event handler forwards push notifications to other push event handlers in the host app.
+
+     But, what if the CIO SDK event handler forwards a push event back to the CIO SDK event handler? This could cause an infinite loop.
+
+     This test simulates that scenario to make sure that an inifinite loop would not happen.
+     */
+    func test_onPushAction_expectNoInfiniteLoopIfSdkForwardsPushEventBacktoSdkAgain() {
+        // The push event handler proxy is what forwards push events to other push event handlers in the app.
+        // To test if an infinite loop would happen, add ourself as a push event handler to get events forwarded to.
+        pushEventHandlerProxy.addPushEventHandler(pushEventHandler)
+
+        // Make sure push is not from CIO otherwise event does not get forwarded.
+        let givenPush = PushNotificationStub.getPushNotSentFromCIO()
+
+        // Send the CIO SDK push event handler an event. If an infinite loop occurs, this test will timeout or crash.
+        pushEventHandler.onPushAction(PushNotificationActionStub(push: givenPush, didClickOnPush: true)) {}
+    }
+}