To make sure your application is running bug-free while also meeting every expected outcome accordingly, you'll need to write tests. Testing is the process whereby an application or software goes through validation, either automated or manually, to examine its current behavior against the intended outcome.
In this post, we'll look at some of the significant differences between Appium and Espresso as automated testing tools. We'll also look at some reasons why you might choose one over the other as your next automated testing tool.
Appium is an automated testing tool that helps you to script automated tests for native iOS or Android and Windows desktop applications. With this in mind, Appium is a very helpful tool for testers and developers who are working on tests for multiple platforms. It doesn't just support native or desktop apps but even progressive web apps (PWAs). One of its major advantages is the ability to support automation for multiple platforms.
Let's talk about some of the advantages you get with Appium and why it might be the next automation tool you could use for testing your native application. Below are some of the advantages you get when using Appium for testing.
Appium comes with support for APK, IPA, and Windows SDKs. You don't need to recompile or change anything to automate your native application.
Easy for Teams
Suited for Growing an App
If you're using Appium to test an app that was initially for a specific platform (e.g., iOS) and then later introduced to another platform (e.g., Android), you'll have the advantage of using the same test scripts to test both platforms without having to write new tests for different platforms separately when your app is growing. Appium supports single automation for both platforms out of the box.
We all know for everything good, there is an ugly side—well, maybe not so ugly. Below we're going to talk about some of the reasons Appium might not be the best option for you as a testing tool and why. But in no way does it means Appium is a bad testing tool. Most times, it's about preference and what works best for your application.
Because Appium doesn't know the platform you're testing for, it will have to go through some steps before a command is then executed.
Let's look at an example. Say you have a test script that fires a command to click a button. The test script makes a library call to decide which native platform (iOS, Android) it is trying to connect to, then converts it to a WebDriver, after which it communicates with the Appium server, which is connected to the platform-specific device (iOS, Android). Then it talks to the native UI test driver, after which it is then converted to a JSON wire protocol passing it to the WebDriver agent, which is then executed to the native platform test. This would be Espresso for Android or XCUITest for iOS.
A single test command has to go through all of these stages before it is executed. Just imagine having more commands. And each of these commands affects your speed.
Platform UI Updates
In native testing tools, every new UI update is immediately supported. Because Appium is not a platform-specific native testing tool, some of the UI updates take a long time before they're then rolled in—unlike native testing tools that are made to test only specific native platform apps (e.g., XCUITest, iOS). And this can affect development.
Continuous Integration (CI)
It might be an advantage that Appium supports multiple languages and frameworks, but maybe not in all cases. When it comes to continuous integration, you'll want to make sure that your development tools are compatible with the ones you're using in your CI/CD for an easy setup. In this case, DevOps teams might be using different tools from the one the QA team is using with Appium, which might cause integrating CI/CD to be a tricky task. Native testing tools, on the other hand, use the same technology for both development and testing, making it easy to set up CI/CD. But a tester with experience will not find this to be an issue.
Espresso is a native automated testing tool for testing an Android application's UI. It was developed by Google in 2013. It comes with a minimal boilerplate, making it easy and fast for developers to test the UI of their applications. Unlike Appium, Espresso is a testing tool used for automating native Android apps. It also requires some understanding of the application codebase to be able to write automation hitch-free.
Major Components of Espresso
Espresso wants the tester to think like the user interacting with the application—from locating UI elements to using them to interact with the application. But it also wants to make sure it prevents direct access to activities and views of the application because operating on them directly can cause test flakiness. To avoid flakiness in your tests while interacting with the UI, you can use these three major components of Espresso:
ViewMatchers: This allows you to get a UI element from the view (e.g., Buttons, TextFields, CheckBoxes).
ViewActions: After finding a UI element, you would want to perform an action with it. The ViewActions component allows you to perform actions on the view using the UI elements (e.g., clicks, scrolling).
ViewAssertions: The whole point of testing is to make sure that what we're getting corresponds with what we're expecting. ViewAssertions helps to check if those two things tally in the automation process.
Now let us look at some of the advantages you can get from using Espresso for testing your Android application.
Espresso and Android are both Google products. Because of this, Espresso will get UI updates immediately after the updates are live on the Android platform, which makes it easy for native testers to test apps against new updates faster without having to wait for an update. This means all your tests are going to be up to date with the current UI changes.
Because Espresso test scripts are written and executed within the app, some of the implementations and logic are done automatically, reducing unnecessary boilerplates. This makes writing tests faster and more convenient for testers.
The programming language and framework used to program the app are the same as the ones used for writing tests. This makes it easy for the DevOps team to integrate CI/CD with the same tool and language.
Easy to Maintain
Espresso allows you to write your test script within your application, which makes your test results available instantly. This means it's easy to maintain because the same developers who wrote the application might have written the test scripts.
Some of the disadvantages of using Espresso involve the following.
Espresso is a UI testing tool for validating only Android applications.
With Espresso, you can only write your test scripts with Java or Kotlin as a framework. This will make it hard for testers or programmers coming from different backgrounds to use.
Difficult to Use for a QA Team
Testers or the QA team need to have some understanding of Android development and the codebase to use Espresso. It's a native testing framework only for Android platforms and languages (Java, Kotlin).
Appium vs Espresso: Which Should I Choose for My App and Why?
These two testing tools have similar intentions with different results. Espresso is for testing the UI of a specific mobile platform (Android), while Appium is an automated testing tool used for testing the application behaviors of multiple platforms (iOS, Android, and Windows desktop applications) using a programming language or framework of your choice. In as much as you can use both tools together, you might also want to use them individually to achieve a better outcome.
If you or your team are working on a mobile application that will run for only the Android platform, which is very unlikely these days, you should consider using the Espresso framework for your testing, as it comes with advantages for Android apps—for instance, speed, easy maintenance, ease of adoption, CI/CD. But in a situation whereby you or your team are working on a native app for multiple platforms, Appium should come in handy for your automation for the advantages it gives you—multiple platform support and multiple languages support, for example.
The best way to choose between these two automated testing tools is to examine the amount of resources, money, and time it will take to implement one over the other in your application. It can also come down to your preference and what you feel comfortable with.