Native mobile app testing: A detailed introduction

What is native mobile app testing?

Native mobile app testing involves examining apps to ensure they function correctly, offer a seamless user experience, and work well with their intended mobile operating systems.

Native apps are apps made for specific mobile operating systems. iOS devices like iPhones and iPads use apps primarily coded in Swift, whereas Android devices use Java or Kotlin. Let’s dive a little deeper into what makes native apps unique.

Native vs. non-native vs. hybrid mobile apps

To truly understand native mobile apps, we must differentiate them from non-native (web-based) and hybrid apps.

1. Native apps: With direct access to device features and optimized performance, native apps provide optimal performance and allow developers to build better user experiences.
2. Web apps: More akin to websites, web apps mimic apps but aren’t actually installed on a device. They run via web browsers and are generally more universal but can’t harness the device’s full capabilities.
3. Hybrid apps: Using web technologies within a native wrapper, hybrid apps can use device features while retaining web apps’ universality.

Native mobile app testing zeroes in on platform-specific nuances, maximizing device capabilities and ensuring the best performance.

Principles of native mobile app testing

Whether you’re a startup or a tech giant, the principles of native app testing are consistent. Let’s break it down step by step:

1. Device selection
   With countless devices on the market, selection is critical. Choosing devices that your user base prefers is usually the best idea. You can’t test on every device, but considering factors like screen sizes, OS versions, and hardware configurations can give you a solid representative sample.
2. Test environment setup
   Where you test can be as crucial as what you test. While real devices offer true-to-life results, emulators or simulators provide a controlled environment. They mimic devices’ software and hardware behaviors, which can be exceptionally handy when real devices are not available.
3. The multiverse of tests
   When we talk about mobile app testing, it isn’t just one monolithic activity. It’s an amalgam of:
   • Functional testing:
     The backbone. Does your app do what it’s supposed to do?
   • Performance testing:
     Beyond functionality. How fast? How smooth? How efficient?
   • Security testing:
     In a data-driven age, security isn’t optional. Are user data and connections secure?
   • Usability testing:
     It’s all about the user. Is the app intuitive, user-friendly, and delightful?
   • Compatibility testing:
     With diverse devices and OS versions, ensuring universal functionality is crucial. Does your app perform equally on all devices?
4. The manual vs. automation dilemma
   Automation is the future. Automated testing, which leverages test recording, model-based testing, or scripting, is a game-changer for repetitive tasks. Products like Testim Mobile streamline iOS and Android testing, making automation an especially attractive proposition.
5. Embrace emulators
   Emulators aren’t just convenient; they’re lifesavers. Tools like the Android Studio’s built- in emulator simulate numerous devices and scenarios and offer early-stage testing solutions that can be both wide-ranging and specific.
6. Feedback is gold
   In testing and development, feedback isn’t just helpful, it’s the bedrock of improvement. Setting up efficient feedback loops, collecting data, addressing bugs, and retesting can enhance app quality multifold.

Challenges in native mobile app testing

• Diverse devices and screen resolutions: With countless devices available on the market, each with its unique screen resolution and hardware capabilities, ensuring consistent app behavior across all devices is challenging.
• Constant OS updates: Operating systems are frequently updated, especially in the mobile realm. Each update can introduce changes that affect app performance, leading to potential bugs or incompatibilities.
• Resource availability: Native mobile app testing requires a significant investment in time, devices, and sometimes even human resources. This can strain the resources of smaller development teams.
• Varied network conditions: Different users access apps under various network conditions, from high-speed Wi-Fi to 3G. Ensuring the app functions seamlessly across these conditions can be tough.
• Localization and internationalization: For apps targeting a global audience, testing must account for different languages, cultural nuances, and even regional legal requirements.

Best practices for native mobile app testing

1. Automate repetitive tasks: While manual testing is essential for certain aspects like usability, automating repetitive tests can save time and reduce errors. Tools like Testim Mobile are invaluable for automating iOS and Android mobile app testing.
2. Stay updated with OS releases: Subscribe to updates from platform developers, such as Apple and Google, so you’re informed about upcoming changes. This proactive approach can help you anticipate issues before they impact users.
3. Prioritize user experience: Beyond just functionality, ensure the app delivers a smooth and intuitive experience. Regularly gather user feedback and make necessary adjustments.
4. Embrace Continuous Integration (CI): Implementing CI practices allows for faster detection of issues and more frequent code integrations, leading to faster and easier high-quality delivery of new features to the customers.
5. Test in real-world conditions: While lab testing is controlled and consistent, testing apps under actual conditions is essential. This includes varied network conditions, battery levels, interruptions like calls or notifications, and more.
6. Maintain a device lab: While emulators and simulators are handy, having a range of physical devices, primarily those popular in your target market, can provide more accurate testing results. Rotate devices to keep the lab updated.
7. Collaborate and communicate: Ensure testers, developers, and other stakeholders maintain open lines of communication. Sharing insights, challenges, and feedback can lead to a more efficient testing process and a better product.

Testing an Android app

Let’s create a simple scenario.

Suppose you have an Android app with a login screen. The login screen consists of two fields (username and password) and a login button. You want to test the functionality of the login process.

We’ll use the popular Android testing framework Espresso for this example.

First, make sure you have the necessary dependencies in your build.gradle file:

androidTestImplementation’ androidx.test.espresso:espresso-core:3.3.0′
androidTestImplementation’ androidx.test:runner:1.3.0′
androidTestImplementation’ androidx.test:rules:1.3.0′

Now, let’s write the test:
package com.example.myapp;

import androidx.test.espresso.Espresso;
import androidx.test.espresso.matcher.ViewMatchers;
import androidx.test.rule.ActivityTestRule;
import androidx.test.runner.AndroidJUnit4;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;
import static androidx.test.espresso.action.ViewActions.click;
import static androidx.test.espresso.action.ViewActions.typeText;
import static androidx.test.espresso.assertion.ViewAssertions.matches;
import static androidx.test.espresso.matcher.ViewMatchers.isDisplayed;

@RunWith(AndroidJUnit4.class)
public class LoginActivityTest {

@Rule
public ActivityTestRule mActivityRule = new ActivityTestRule<>(LoginActivity.class);

@Test
public void login_withValidCredentials_displaysWelcomeMessage() {
// Input username
Espresso.onView(ViewMatchers.withId(R.id.username))
.perform(typeText(“testUser”));

// Input password
Espresso.onView(ViewMatchers.withId(R.id.password))
.perform(typeText(“testPass123”));

// Click on the login button
Espresso.onView(ViewMatchers.withId(R.id.loginButton))
.perform(click());

// Check if the welcome message is displayed after a successful login
Espresso.onView(ViewMatchers.withText(“Welcome, testUser!”))
.check(matches(isDisplayed()));
}
}

Here’s a breakdown of what the code does:

1. Set up: The test sets up an activity test rule for LoginActivity, which is the activity under test.
2. Input username and password: The test uses Espresso to find the username and password fields by their IDs and types in test credentials.
3. Click on the login button: The test then finds the loginButton and simulates a button click.
4. Check welcome message: After “logging in,” the test checks to see whether a welcome message is displayed to confirm a successful login.

This is a basic example, and in real-world scenarios there would be more complexities like handling network requests, database interactions, and more. Furthermore, for actual backend authenticated tests, you’d want to mock the server response or use a dedicated testing environment to avoid altering real data.

Your native mobile app testing checklist

To wrap things up, here’s a handy checklist you can use to guide your tests:

Set up:

• Choose between a real device or an emulator
• Set up the testing environment using tools like Testim Mobile for Android app testing

Functional testing:

• Test all core functionalities
• Check data synchronization

Usability testing:

• Assess user interface and experience
• Test navigation pathways

Performance testing:

• Test the app’s speed
• Check for crashes under heavy loads

Security testing:

• Check for data encryption
• Assess data storage safety

Compatibility testing:

• Test on various devices and OS versions

Summary