{"id":25112,"date":"2022-03-25T10:49:51","date_gmt":"2022-03-25T10:49:51","guid":{"rendered":"https:\/\/www.bacancytechnology.com\/blog\/?p=25112"},"modified":"2024-06-04T08:31:14","modified_gmt":"2024-06-04T08:31:14","slug":"unit-testing-using-mockito-in-android","status":"publish","type":"post","link":"https:\/\/www.bacancytechnology.com\/blog\/unit-testing-using-mockito-in-android","title":{"rendered":"Unit Testing Using Mockito in Android"},"content":{"rendered":"

Introduction<\/h2>\n

Nowadays mobile applications are getting complex functionalities & bigger in size, that\u2019s why writing test cases is very important to refine code and make sure that each module works properly (I know it is often underestimated among the mobile developer community, sometimes totally ignored!). To write code that is efficiently unit-testable, we should use the best suitable architecture like MVP or MVVM which carries loose coupling into the Android activities\/fragments\/adapter.<\/p>\n

Three different tests developers should consider adding in their test suits:
\n1. UI Tests:<\/strong> These tests are for asserting application UI. Espresso is used.<\/p>\n

2. Instrumented Tests:<\/strong> When we want to verify user actions like button click etc these tests run on Android devices, whether physical or emulated taking the advantage of APIs provided by the Android framework. AndroidX Test & Espresso is widely used for the same.<\/p>\n

3. Unit Tests:<\/strong> Unit tests are more important for testing every function and procedure in the application. For unit testing, mostly used tools are JUnit, Mockito, or Hamcrest.<\/p>\n

The main objective of Unit Testing is to fix bugs early in the development cycle by verifying the correctness of code. In this tutorial, we will learn how what is Mockito and the steps to implement unit testing using Mockito in Android application. <\/p>\n

Why Mockito?<\/h2>\n

Often we have classes with dependencies and methods being dependent on another method of a different class. When we are unit testing such methods, we want the unit tests to be independent of all other dependencies. That\u2019s why we will Mock the dependency class using Mockito and test the main class. We can not achieve this using JUnit.<\/p>\n

Testing outcomes become the stories we tell our future generations of developers at Bacancy.<\/span>
\nHire Android developer<\/a> from the award-winning App Development Company to stand out in the market and become the star-solution with your business idea.<\/i><\/strong><\/p>\n

Now moving towards our demo application. <\/p>\n

Steps: Unit Testing using Mockito in Android<\/h2>\n

Let\u2019s take a simple example of computations like addition, subtraction, etc to understand the Mockito framework. <\/p>\n

We will create a file ComputationActivity.kt<\/i> to display all computations upfront. For managing all operations we will create object class Operations.kt which will be passed to ComputationActivity<\/i> class as a param in the primary constructor.<\/p>\n

class ComputationActivity(private val operators: Operations) {\r\n   fun getAddition(x: Int, y: Int): Int = operators.add(x, y)\r\n   fun getSubtraction(x: Int, y: Int): Int = operators.subtract(x, y)\r\n   fun getMultiplication(x: Int, y: Int): Int = operators.multiply(x, y)\r\n   fun getDivision(x: Int, y: Int): Int = operators.divide(x, y)\r\n}\r\n<\/pre>\n
Operations.kt class will look like this which will handle computation functions.<\/p>\n
object Operations {\r\n   fun add(x: Int, y: Int): Int = x + y\r\n   fun subtract(x: Int, y: Int): Int = x - y\r\n   fun multiply(x: Int, y: Int): Int = x * y\r\n   fun divide(x: Int, y: Int): Int = x \/ y\r\n}<\/pre>\n
Add dependencies needed to integrate Mockito in the build.gradle file.<\/p>\n
We will use testImplementation<\/i> which applies to the local test source, not the application.<\/p>\n
testImplementation 'junit:junit:4.13.2'\r\ntestImplementation 'org.mockito:mockito-core:2.25.0'\r\ntestImplementation 'org.mockito:mockito-inline:2.13.0'<\/pre>\n
Folder structure for adding ComputationTest.kt file<\/strong> for testing ComputationActivity.kt<\/strong> class.<\/p>\n
By default, module-name\/src\/test<\/i> will be having source files for local unit tests. <\/p>\n
\"source<\/p>\n
Now, we will add test functions in our  ComputationTest.kt file<\/p>\n