Testing is an essential part of the Android app development process. It helps to ensure that the app works as expected, is bug-free, and provides a seamless user experience. Android offers various testing tools and frameworks that can be used to write and execute different types of tests, including unit tests, integration tests, and UI tests.
Step 1: Create a New Project in Android Studio
Here is an example of an Android app that includes a simple calculator feature, and includes a unit test to verify that the calculator is functioning correctly. To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio . The code for that has been given in Kotlin Programming Language for Android.
Step 2: Working with the activity_main.xml file
Navigate to the app > res > layout > activity_main.xml and add the below code to that file. Below is the code for the activity_main.xml file. Comments are added inside the code to understand the code in more detail.
Step 3: Working with the MainActivity File
Go to the MainActivity File and refer to the following code. Since there is no change in MainActivity File, keep it as it is. This code sets up the UI elements and adds listeners to the Buttons. When a Button is clicked, it calls a method to add a number or operation to the TextView. The calculation method will eventually perform the actual calculations.
Step 4: Working with the MainActivity Unit Testing File
Finally, we can create a unit test for the calculation method.
Kotlin
Output:

Android testing is an essential part of the app development process. It helps to ensure that the app works as expected, is bug-free, and provides a seamless user experience. There are various testing tools and frameworks available for Android, including JUnit, Espresso, UI Automator, Robolectric, and Mockito. By following best practices for Android testing, developers can write tests that are effective, efficient, and maintainable.