Appium vs Espresso for Mobile App Testing: A Comparative Analysis

In the rapidly evolving world of mobile app development, it is necessary to ensure the cross-compatibility of test cases on a wide range of devices and platforms. Testing frameworks play a vital role in this process, aiding developers and test engineers to build robust and bug-free applications. Among the varied options for mobile app testing, Appium and Espresso stand out. Appium is an open source automation testing framework, whereas Espresso is a testing framework developed by Google.

In this blog on Appium vs Espresso, we will compare these frameworks by exploring various features, advantages, use cases, etc.

Let’s get started!

Appium: Unleashing the Cross-Platform Potential

Appium is an open-source test automation framework for mobile applications. It allows you to write tests against multiple platforms (iOS, Android, and Windows) using the same API. It supports multiple programming languages such as Java, Python, Ruby, JavaScript, etc. Appium works by interacting with the UI elements of the application using the WebDriver protocol. It doesn’t require you to modify your application code, which makes it suitable for testing native, hybrid, and mobile web applications.

Key Features of Appium:

Cross-Platform Compatibility: Appium offers the advantage of testing applications on various platforms like iOS, Android, and Windows. This feature enables QA teams to create tests once and run them on different operating systems, ultimately saving time and resources.

Language Diversity: Appium supports a wide range of programming languages such as Java, Python, Ruby, and JavaScript. This flexibility allows developers and QA engineers to select their preferred language for scripting tests, promoting efficiency and teamwork.

UI Automation: Appium interacts with mobile app UI elements using the WebDriver protocol. This helps testers to automate user actions like button clicks, text input, and swipe gestures. This method accurately replicates real user behavior during testing.

Integration with CI/CD Pipelines: Appium seamlessly integrates with Continuous Integration/Continuous Deployment (CI/CD) pipelines, enabling automated testing as part of the software development lifecycle. By incorporating Appium into CI/CD workflows, teams can automate the testing process, identify defects early, and accelerate the delivery of high-quality mobile applications to end-users.

Device Agnostic Testing: Appium supports testing on both real devices and emulators/simulators, allowing QA teams to validate app behavior across a wide range of device configurations. This device agnostic approach ensures comprehensive test coverage and helps identify platform-specific issues early in the development cycle.

Having understood the various features, let’s now take a look at the limitations of Appium.

Limitations

Speed is the main constraint when we talk about the limitations of Appium. Due to its complex architecture, initiating a server instance and communicating effectively takes some time.
As we have mentioned above, Appium is best suited for UI testing. On the contrary, it is not suited for non UI based testing.
Appium tests may encounter flakiness or stability issues, especially when interacting with dynamic elements, or asynchronous behavior within the application. Test flakiness can lead to false positives/negatives and make it challenging to maintain reliable test suites over time.
Automating test cases using Appium
This test case illustrates a basic login scenario using Appium. Depending on the application’s complexity and requirements, you can extend this test case by adding more steps and assertions to cover additional functionalities and edge cases.

Replace “com.example.app” with the actual package name of your mobile application.
Replace “your_username” and “your_password” with valid credentials for testing.
Ensure that the element IDs (“com.example.app:id/…”) used in the script correspond to the correct identifiers in the application’s UI.
import io.appium.java_client.AppiumDriver;
import io.appium.java_client.MobileElement;
import io.appium.java_client.android.AndroidDriver;
import io.appium.java_client.remote.AndroidMobileCapabilityType;
import io.appium.java_client.remote.MobileCapabilityType;
import org.openqa.selenium.remote.DesiredCapabilities;
import java.net.URL;
import java.util.concurrent.TimeUnit;
public class AppiumTest{
public static void main(String[] args) {
// Set the Desired Capabilities
DesiredCapabilities caps = new DesiredCapabilities();
caps.setCapability(MobileCapabilityType.PLATFORM_NAME, "Android");
caps.setCapability(MobileCapabilityType.DEVICE_NAME, "Add a emulator name");
caps.setCapability(AndroidMobileCapabilityType.APP_PACKAGE, "com.example.app");
caps.setCapability(AndroidMobileCapabilityType.APP_ACTIVITY, "com.example.app.MainActivity");

    // Initialize the Appium driver
    AppiumDriver<MobileElement> driver;
    try {
        driver = new AndroidDriver<>(new URL("http://localhost:4723/wd/hub"), caps);
    } catch (Exception e) {
        System.out.println("Error due to initializing Appium driver: " + e.getMessage());
        return;
    }

    // Implicitly wait for elements to be present
    driver.manage().timeouts().implicitlyWait(20, TimeUnit.SECONDS);

    // Perform login
    MobileElement usernameField = driver.findElementById("com.example.app:id/usernameField");
    usernameField.sendKeys("your_username");

    MobileElement passwordField = driver.findElementById("com.example.app:id/passwordField");
    passwordField.sendKeys("your_password");

    MobileElement loginButton = driver.findElementById("com.example.app:id/loginButton");
    loginButton.click();

    // Verify login success
    MobileElement homeScreen = driver.findElementById("com.example.app:id/homeScreen");
    if (homeScreen.isDisplayed()) {
        System.out.println("Login successful! ");
    } else {
        System.out.println("Login failed!");
    }

    // Close the driver session
    driver.quit();
}

}
This is how you can write an Appium test case. Now let’s gain some insights on Espresso.

Espresso: The Google Test Master

Espresso, a widely used testing framework, empowers developers to create automation test cases primarily for UI testing. Developed by Google, it aims to provide a straightforward yet powerful framework. Espresso is highly favored among QA professionals and is extensively utilized as an Android app testing framework.

Key Features of Espresso

Android-centric Testing: Espresso is specifically designed for testing Android apps, utilizing deep integration with the Android platform and APIs. This specialization enables Espresso to offer precise and efficient testing capabilities that are optimized for the complexities of Android app development.

In-process Testing: In contrast to Appium, which interacts with applications externally through UI elements, Espresso runs tests directly within the app’s process. This in-process testing approach allows Espresso to have minimal overhead and fast execution speed, resulting in faster feedback loops during the development process.

Concise API: Espresso provides a concise and intuitive API for writing UI tests, allowing developers to express test scenarios in a clear and declarative manner. With its fluent syntax and built-in synchronization mechanisms, Espresso makes it easy to create robust and maintainable test suites with minimal effort.

Integration with Android Studio: Espresso seamlessly integrates with Android Studio, the official IDE for Android app development. This integration streamlines the testing workflow by offering features such as test recording, debugging, and effortless deployment to physical devices or emulators.

Limitations of Espresso
Espresso has a couple of limitations. They are as follows:

Programming Language Support: Espresso is limited to Java and Kotlin, which means developers who prefer other languages like Python or JavaScript won’t be able to use it directly for testing Android applications.
Platform Support: Espresso is specifically designed for testing Android applications. It doesn’t support cross-platform testing, meaning it can’t be used to test applications on iOS or other platforms.
Synchronous UI Operations: Espresso is primarily designed for testing synchronous UI operations. While it does offer some support for handling asynchronous operations, it’s not as robust as tools specifically designed for testing asynchronous behavior, which can be a limitation depending on the complexity of the application being tested.
Automating a test case using Espresso: A simple use case
This test case illustrates a basic login scenario using Appium. Depending on the application’s complexity and requirements, you can extend this test case by adding more steps and assertions to cover additional functionalities and edge cases.

import androidx.test.espresso.Espresso;
import androidx.test.espresso.action.ViewActions;
import androidx.test.espresso.matcher.ViewMatchers;
import androidx.test.ext.junit.rules.ActivityScenarioRule;
import org.junit.Rule;
import org.junit.Test;
import com.example.myapp.MainActivity;
public class EspressoTest {
@Rule
public ActivityScenarioRule activityScenarioRule = new ActivityScenarioRule<>(MainActivity.class);
@test
public void testLogin() {
// Enter valid username
Espresso.onView(ViewMatchers.withId(R.id.usernameField))
.perform(ViewActions.typeText("your_username"), ViewActions.closeSoftKeyboard());
// Enter valid password
Espresso.onView(ViewMatchers.withId(R.id.passwordField))
.perform(ViewActions.typeText("your_password"), ViewActions.closeSoftKeyboard());
// Click on the Login button
Espresso.onView(ViewMatchers.withId(R.id.loginButton)).perform(ViewActions.click());
// Verify if the user is redirected to the home screen
Espresso.onView(ViewMatchers.withId(R.id.homeScreen))
.check(ViewAssertions.matches(ViewMatchers.isDisplayed()));
// Optionally, verify user's profile information
// Espresso.onView(ViewMatchers.withId(R.id.profileInfo))
// .check(ViewAssertions.matches(ViewMatchers.withText("Expected Profile Information")));
}
}
This is how we write Espresso test cases. Now that you have understood the fundamental concepts of Appium and Espresso, let’s understand the key differences of these testing tools.

Appium vs Espresso: Key Differences

As we have learnt various fundamentals of both the testing frameworks, let’s gather all together in a nutshell. Below table shows the various functionalities and how Appium and Espresso differ from each other.

Now that you have understood the key differences of both of these frameworks, let’s understand which framework is best suited for test cases.

Appium vs Espresso: Which is the best fit?

When it comes to choosing between Appium and Espresso for mobile app testing, the decision depends on various factors such as project requirements, team expertise, and target platforms. Here are some points to consider:

Cross-Platform Testing: If your project involves testing applications across multiple platforms like iOS, Android, and Windows, Appium’s cross-platform support makes it an excellent choice.

Android App Testing: For teams which mainly focus on Android app development, Espresso’s deep integration with the Android platform and superior performance make it the preferred option.

Programming Language Preference: Take into account the programming languages supported by each framework and select the one that aligns with your team’s expertise and preferences.

Speed and Efficiency: If speed and efficiency are crucial, especially for rapid feedback in continuous integration pipelines, Espresso’s in-process testing approach provides significant advantages in terms of execution speed and reliability.

In conclusion, both Appium and Espresso are robust testing frameworks with unique strengths and use cases. By understanding their features and capabilities, teams can make informed decisions to ensure effective testing strategies and deliver high-quality mobile applications to end-users. Whether it’s cross-platform testing with Appium or Android-specific testing with Espresso, the ultimate goal remains the same: to build mobile apps that delight users and stand the test of time.

Source: This blog was originally posted on Testgrid.