Espresso is a test framework used to write Android UI tests, and part of the Android SDK. The Espresso API encourages test authors to think in terms of what a user might do while interacting with the application - locating UI elements and interacting with them. At the same time, the framework prevents direct access to activities and views of the application because holding on to these objects and operating on them off the UI thread is a major source of test flakiness.
Appium works well for well-structured mobile applications test automation that is particularly easy to leverage when different pages of the app use similar building blocks. If it takes time for some content in the app to be rendered, ask your dev team to add progress indicators and ensure they are accessible. That might be more complicated to do with Appium, though, if there's no good contact with Dev team established so you can request accessibility IDs added quickly enough when needed. Appium supports another locator strategies as well though (such as xPath or iOS class chain on iOS) but they wouldn't work as fast so you may get really slow tests.
There are a number of expected methods that are not implemented, yet. With a similar sounding name as Selenium with similar functions, people who are familiar with Selenium try to use methods that appear to be available, but give a "not yet implemented" exception when run.
Documentation can be confusing.
Setup was a difficult process. This may not necessarily be the case once you figure everything out, but the whole figuring it out process was difficult and I ran into many, many problems when I first started.
As Espresso works on the ideal thread if the threads are not handled properly by the developing team it can lead to challenges in the execution of your tests.
Depends more on the developer's code
we cannot develop tests as individual frameworks, we share the repository with developers.
We need to be cautious while making changes in the tests, as we share same repository
I would like to give 9/10 rating to Appium because of it can easily integrate with popular frameworks and CI/CD tools, as well as it is reliable, flexible and easy to use. The setup can bit complex in initial step, but once on configured it's very easy to use and enables stable and scalable mobile automation for real and cloud devices.
Most of mobile testing tools which are available in the market are paid license tools. But Appium is Open source mobile testing tool. We can create customised automation framework using Appium. It also supports various languages such as Java, Javascript etc. And also supports various operating systems such as Android, IOS etc. We can easily integrate Appium frameworks with CI/CD [Jenkins, Git etc].
As our app is complete on Android Espresso is the best choice over Appium Fewer efforts in Espresso over Appium, as Espresso provides some built-in library to perform the operation. Easy to use, Espresso is very easy to understand and we can perform operations with very little code. Developers can contribute, as they have good command over Java and Kotin languages and also use Espresso for unit testing.