Here's How to Test iOS Apps Across Different States and Lifecycle Stages 10 Different Ways

In this article I’m going to talk about the lifecycle and states of apps for iPhone and iPad. But wait—why should you care? Let me explain:By understanding how an app moves through states, you can catch sneaky bugs, simulate real-world scenarios and make sure everything runs smoothly—even when the app is doing something in the background. What are the lifecycle and states of an app? Imagine your app is like a person going through different parts of their day. Each part of their day is a state, and the transitions between these states make up the lifecycle. Here’s how it works: states Active state When the app is being actively used by the user (for example, navigating through screens, interacting with the interface, or receiving real-time updates), it is in the active state. This is the normal running state of the app. Background state When you switch focus to a second app, that app becomes the active one. However, if the app you were just using has tasks configured to run in the background (like downloading data or location tracking), it will continue to run these tasks even though it's not actively visible to the user. We say that the app is now in the background state. background state To simulate the background state, swipe the app up or switch to another app through the App Switcher. The app will be sent to the background and may perform tasks like downloading content, syncing data, or listening for push notifications. Suspended state The app moves to the suspended state when it is sent to the background and isn't actively performing any tasks like background downloads or updates. suspended In the suspended state, the app doesn’t consume resources but is still in the background until terminated by the system or user. suspended If you quickly switch away from your app and return to it, it may appear to reload or refresh as if it had been suspended. Typically, apps in the suspended state don’t perform any active tasks or use resources. suspended Inactive state If you're actively using the app and you receive an incoming call or an alert, the app may briefly enter the inactive state. Once the interruption has ended and you bring focus back to the app, it is again in the active state. inactive Not running If you swipe the app up from the App Switcher and close it, the app is no longer running. In some cases, the operating system will allow the app to run background tasks for a few seconds before completely terminating it, if those tasks were critical. You can determine the app is not running if you attempt to open it and it has to launch from scratch, showing the app's splash screen. not running Testing through app lifecycle: tips and tricks When you are testing an iOS app, it’s important to ensure it behaves correctly across various states. For example: If the app isn’t running, you need to verify how it handles cold starts, making sure it loads data and UI without delays. While the app is in the background, you should check that it performs assigned tasks (like refreshing content or processing uploads) within the resource limits of iOS. You should also examine transitions between states to ensure smooth handling with no glitches, lags, or data loss. Finally, you should test interruptions and ensure the app has a proper response. If the app isn’t running, you need to verify how it handles cold starts, making sure it loads data and UI without delays. While the app is in the background, you should check that it performs assigned tasks (like refreshing content or processing uploads) within the resource limits of iOS. You should also examine transitions between states to ensure smooth handling with no glitches, lags, or data loss. Finally, you should test interruptions and ensure the app has a proper response. Here are some test scenarios you might find useful: App is suspended with ongoing tasks App is suspended with ongoing tasks What is tested: How the app handles long-running tasks like file uploads or data processing when it is suspended. What is tested: Why this is tricky: iOS freezes the app in a suspended state, but certain tasks like background uploads may still need to continue. If not managed correctly, the app could lose data or fail to complete tasks. Why this is tricky: How to test it: How to test it: Start a long-running task like file upload. Put the app in the background and leave it for an extended period (several minutes to hours). You can do this by opening another app and using it briefly. Check if the task you started in step 1 finishes successfully once the app is resumed or reopened. Verify that the app doesn’t fail or lose progress due to suspension. Start a long-running task like file upload. Put the app in the background and leave it for an extended period (several minutes to hours). You can do this by opening another app and using it briefly. Check if the task you started in step 1 finishes successfully once the app is resumed or reopened. Verify that the app doesn’t fail or lose progress due to suspension. App is terminated by the system while in the background App is terminated by the system while in the background What is tested: How the app behaves when it’s terminated by the system due to low resources (memory or battery). What is tested: Why this is tricky: iOS may force an app to quit if the system needs resources. This can happen while the app is in the background, and apps may need to handle state restoration or data persistence when relaunched. Why this is tricky: How to test it: How to test it: Put the app in the background and initiate a memory-intensive task like heavy data processing or video streaming. Simulate a memory warning or force-quit the app through the app switcher. Relaunch the app and verify if it restores user data, session, and previous state correctly. Check if there’s any data loss or crash upon reopening. Put the app in the background and initiate a memory-intensive task like heavy data processing or video streaming. Simulate a memory warning or force-quit the app through the app switcher. Relaunch the app and verify if it restores user data, session, and previous state correctly. Check if there’s any data loss or crash upon reopening. App is put in the background during user input App is put in the background during user input What is tested: How the app handles user input or form submissions during which the app is sent to the background. What is tested: Why this is tricky: If the app transitions to the background while the user is actively entering data, the app must correctly save the data to avoid loss. The app may also need to handle unfinished tasks like submitting forms when coming back to the foreground. Why this is tricky: How to test it: How to test it: Begin entering data in a form or text field. Move the app to the background (for example, press the Home button). Return to the app and check if the form or text field data was saved correctly. Ensure that the user is not presented with an incomplete form or error message when returning to the app. Begin entering data in a form or text field. Move the app to the background (for example, press the Home button). Return to the app and check if the form or text field data was saved correctly. Ensure that the user is not presented with an incomplete form or error message when returning to the app. Push notifications received during suspended state Push notifications received during suspended state What is tested: How the app handles push notifications when it is suspended or not actively running. What is tested: Why this is tricky: Notifications can be received while the app is suspended or not running at all. The app must handle these notifications appropriately either by showing an alert, updating the UI when it comes back to the foreground, or performing background tasks (if allowed). Why this is tricky: How to test it: How to test it: Suspend the app (let it run in the background for an extended period). Send a push notification while the app is in the suspended state. When the app is resumed, check how it handles the notification: Does it update the UI correctly? Does it display the correct screen? Is there any delay or missed notification? Suspend the app (let it run in the background for an extended period). Send a push notification while the app is in the suspended state. When the app is resumed, check how it handles the notification: Does it update the UI correctly? Does it display the correct screen? Is there any delay or missed notification? Does it update the UI correctly? Does it display the correct screen? Is there any delay or missed notification? Does it update the UI correctly? Does it display the correct screen? Is there any delay or missed notification? Network changes occur during state transitions Network changes occur during state transitions What is tested: How the app handles network connectivity changes (like a change from Wi-Fi to cellular data or a complete network disconnection) while transitioning between different app states (active, background, suspended). What is tested: Why this is tricky: Network changes can disrupt tasks like syncing data or loading content, especially during state transitions. The app must efficiently manage retries, loading states, and error handling. Why this is tricky: How to test it: How to test it: Start a network-dependent task like loading content or syncing data. Switch from Wi-Fi to cellular data or disable the network completely during a state transition (such as moving from background to suspended state). Verify that the app handles the change properly: Does it retry the request or show an error message? Is the task resumed correctly when the network connection is restored? Start a network-dependent task like loading content or syncing data. Switch from Wi-Fi to cellular data or disable the network completely during a state transition (such as moving from background to suspended state). Verify that the app handles the change properly: Does it retry the request or show an error message? Is the task resumed correctly when the network connection is restored? Does it retry the request or show an error message? Is the task resumed correctly when the network connection is restored? Does it retry the request or show an error message? Is the task resumed correctly when the network connection is restored? Handling user defaults or session data after suspension Handling user defaults or session data after suspension What is tested: How the app handles saving and restoring session data (like user login, preferences, and so on) when the app is suspended and then resumed. What is tested: Why this is tricky: If the app doesn’t save user data properly when suspended, users may lose their place in a flow or have to log in again when they reopen the app. This can cause frustration and poor user experience. Why this is tricky: How to test it: How to test it: Make changes to user data (for example, change preferences or log in). Put the app into the background and leave it there for a while. Return to the app and verify that the data was preserved and the user was not logged out or forced to re-enter information. Make changes to user data (for example, change preferences or log in). Put the app into the background and leave it there for a while. Return to the app and verify that the data was preserved and the user was not logged out or forced to re-enter information. Multiple instances of the app are running at once Multiple instances of the app are running at once What is tested: How the app behaves when multiple instances are running at once (for example, the user is logged in on two different devices), and whether state conflicts arise. What is tested: Why this is tricky: Some apps might not handle multiple sessions properly, leading to data conflicts or errors when the user switches between devices or app instances. Why this is tricky: How to test it: How to test it: Open the app on two devices or in two windows (for example, open the app on an iPhone and then on an iPad). Perform actions that modify user data or session state on the first device. Switch to the second device and check if the changes are reflected correctly or if any conflicts arise. Open the app on two devices or in two windows (for example, open the app on an iPhone and then on an iPad). Perform actions that modify user data or session state on the first device. Switch to the second device and check if the changes are reflected correctly or if any conflicts arise. App usage is interrupted by an event on the device App usage is interrupted by an event on the device What is tested: How the app behaves when interrupted by incoming calls, text messages, or notifications. What is tested: Why this is tricky: The app must ensure that user progress is saved and must resume smoothly after the interruption. Proper handling of interruptions improves the overall user experience and prevents data loss. Why this is tricky: How to test it: How to test it: Incoming call While using the app, simulate an incoming call. Check that the app pauses its activities and saves the current state. For example, if the user is filling out a form, verify that the data is saved. Receiving a text message Simulate receiving a text message while the app is active. Ensure that the app handles the interruption without crashing and that the UI appears as expected upon returning. Notification interruption Trigger a push notification while the app is open. Ensure that the notification doesn’t disrupt the app’s functionality. After dismissing the notification, the app should return to its previous state without glitches. Incoming call While using the app, simulate an incoming call. Check that the app pauses its activities and saves the current state. For example, if the user is filling out a form, verify that the data is saved. Incoming call While using the app, simulate an incoming call. Check that the app pauses its activities and saves the current state. For example, if the user is filling out a form, verify that the data is saved. While using the app, simulate an incoming call. Check that the app pauses its activities and saves the current state. For example, if the user is filling out a form, verify that the data is saved. Receiving a text message Simulate receiving a text message while the app is active. Ensure that the app handles the interruption without crashing and that the UI appears as expected upon returning. Receiving a text message Simulate receiving a text message while the app is active. Ensure that the app handles the interruption without crashing and that the UI appears as expected upon returning. Simulate receiving a text message while the app is active. Ensure that the app handles the interruption without crashing and that the UI appears as expected upon returning. Notification interruption Trigger a push notification while the app is open. Ensure that the notification doesn’t disrupt the app’s functionality. After dismissing the notification, the app should return to its previous state without glitches. Notification interruption Trigger a push notification while the app is open. Ensure that the notification doesn’t disrupt the app’s functionality. After dismissing the notification, the app should return to its previous state without glitches. Trigger a push notification while the app is open. Ensure that the notification doesn’t disrupt the app’s functionality. After dismissing the notification, the app should return to its previous state without glitches. Switching between apps (multitasking) Switching between apps (multitasking) What is tested: How the app behaves when users switch between apps. What is tested: Why this is tricky: iOS allows fast switching between apps, so ensuring that your app maintains its state when returning is critical for user engagement. Why this is tricky: How to test it: How to test it: App switching Open the app, then switch to another app. Return to the original app and verify that the last-used state is restored correctly. If the user was on a specific screen, they should see that exact screen. State preservation Navigate through multiple screens in the app. Switch to another app and return to the original app. Verify that the navigation stack is intact, and the user can return to previously viewed screens without loss of data or state. App switching Open the app, then switch to another app. Return to the original app and verify that the last-used state is restored correctly. If the user was on a specific screen, they should see that exact screen. App switching Open the app, then switch to another app. Return to the original app and verify that the last-used state is restored correctly. If the user was on a specific screen, they should see that exact screen. Open the app, then switch to another app. Return to the original app and verify that the last-used state is restored correctly. If the user was on a specific screen, they should see that exact screen. State preservation Navigate through multiple screens in the app. Switch to another app and return to the original app. Verify that the navigation stack is intact, and the user can return to previously viewed screens without loss of data or state. State preservation Navigate through multiple screens in the app. Switch to another app and return to the original app. Verify that the navigation stack is intact, and the user can return to previously viewed screens without loss of data or state. Navigate through multiple screens in the app. Switch to another app and return to the original app. Verify that the navigation stack is intact, and the user can return to previously viewed screens without loss of data or state. Task handling while app is running in the background Task handling while app is running in the background What is tested: How the app handles background tasks such as downloading or syncing data while the app is in the background. What is tested: Why this is tricky: You should ensure that background tasks continue efficiently and that the user receives timely updates without draining the device’s resources. Why this is tricky: How to test it: How to test it: Background download Initiate a download task in the app. Switch to another app and allow the download to finish in the background. Return to the app and ensure that the download completion status is shown. Syncing data Start a data sync in the background. Switch to another app and return to the original app. Check that the sync is finished and that updated content is visible without requiring a manual refresh. Background download Initiate a download task in the app. Switch to another app and allow the download to finish in the background. Return to the app and ensure that the download completion status is shown. Background download Initiate a download task in the app. Switch to another app and allow the download to finish in the background. Return to the app and ensure that the download completion status is shown. Initiate a download task in the app. Switch to another app and allow the download to finish in the background. Return to the app and ensure that the download completion status is shown. Syncing data Start a data sync in the background. Switch to another app and return to the original app. Check that the sync is finished and that updated content is visible without requiring a manual refresh. Syncing data Start a data sync in the background. Switch to another app and return to the original app. Check that the sync is finished and that updated content is visible without requiring a manual refresh. Start a data sync in the background. Switch to another app and return to the original app. Check that the sync is finished and that updated content is visible without requiring a manual refresh. To wrap up We have talked about app states in iOS and we explored some key edge cases that could affect your app's functionality and performance. Using these cases in your mobile testing routine can help you prevent data losses, crashes, and unexpected behaviour.