Recently, I developed an Android application. The application was developed focusing on simplicity. The application was small thus skipped writing unit tests. I know skipping the unit tests is not a good practice. In past, I was working on backend projects where tons of unit tests exists for API’s. I am new to application development and spent some time to learn about MVC and MVVM design patterns. For next project, the preference is MVVM. At end of this post I will share the reason to choose MVVM. The example code for this post is written for Android application. MVC (Model-View-Controller) Model: Model is data layer.