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Writing Automated UI Tests with Kakao in Android

April 15, 2022

Instrumented tests ensure that an app functions correctly and as expected. This reduces the number of instances where an application fails during production.

We can perform manual testing, in which we test every feature of our app. However, the manual method is time-consuming and we may fail to test certain components.


To follow along, you should have:

  • Basic knowledge of Android instrument tests.
  • Some basics with Espresso.
  • Android Studio installed on your computer.
  • Good knowledge of creating and running Android apps.
  • Basic knowledge of the Kotlin programming language.


Espresso is a testing framework that allows developers to write instrumented tests in Android.

To understand more on how to write tests with Espresso, please check out this article - Automating UI Tests in Android Using Espresso.

Although Espresso is great, it has its downfalls. For instance, it reduces code readability and results in a lot of boilerplate code. This is where Kakao comes in.

Kakao is built on top of Espresso and allows one to write more powerful UI tests.

Getting started

In this tutorial, we will write UI tests with Kakao for three Activities.

Step 1 - Setting up the project

Create an empty Android project and give it a name of your choice.

Open your app-level build.gradle and add the following dependencies:

// Kakao
androidTestImplementation 'io.github.kakaocup:kakao:3.0.6'

Make sure the following dependencies are already included, if not, just add them:

androidTestImplementation 'androidx.test.ext:junit:1.1.3'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'

Step 2 - The user interfaces

Because we’ll write automated UI tests, we need multiple UIs to test. Go ahead and design and add the logic of the following layouts:

You can check out the complete code in this Github repository - UI Testing With Kakao Demo.

The repository contains the full implementation of the code. We will focus on testing the user interfaces to make sure they work as expected.


main layout


register layout


search layout

Step 3 - Declaring screens

Kakao uses Screens that contain all the views that a given layout holds. To reference Views from the actual user interface, Kakao uses support views such as KTextView, KImageView, KButton, KRecyclerView and many more.

To create a Screen, create a class that extends Screen, as shown below:

class TestScreen : Screen<TestScreen>(){

To reference Views, declare a variable and use withId to find the id of the actual view:

val testTextview = KTextView{

Now, let’s define all the screens that we will test.

Since UI tests (Instrumented tests) involve using Android components, we will write our test in the androidTest source set. Navigate to the androidTest section and create a new package called screens.


We will create a Screen with two TextViews, ImageView and a Button:

class MainScreen : Screen<MainScreen>(){
    val titleTextview = KTextView{
    val androidImageView = KImageView {
    val changeButton  = KButton {
    val changedTextView = KTextView {


This layout contains several EditTexts, a Button, and a Snackbar:

class RegisterScreen : Screen<RegisterScreen>(){
    val emailEditText = KEditText{
    val nameEditText = KEditText{
    val phoneEditText = KEditText{
    val passwordEditText = KEditText{
    val registerButton = KButton{
    val snackbar = KSnackbar()


This layout contains a search EditText, Button, and a RecyclerView. To define a RecyclerView, you use a KRecyclerView and for the ViewHolder, use KRecyclerItem:

class SearchScreen : Screen<SearchScreen>() {
    val searchEditText = KEditText {
    val searchButton = KButton {withId(R.id.searchButton)}
    val snackbar = KSnackbar()

    val carsRecyclerview = KRecyclerView(
        builder = { withId(R.id.carsRecyclerview)},
        itemTypeBuilder = {itemType(SearchScreen::Item)}

    internal class Item(parent: Matcher<View>) : KRecyclerItem<Item>(parent){
        val name: KTextView = KTextView(parent) {withId(R.id.textViewCarName)}
        val price: KTextView = KTextView(parent) {withId(R.id.textViewCarPrice)}
        val type: KTextView = KTextView(parent) {withId(R.id.textViewCarType)}

Step 4 - Writing tests with Kakao

First, let’s write tests for the MainActivity layout. The layout contains:

  • A TextView with a title.
  • An ImageView with an image.
  • A Button that, when clicked, should change the text.
  • A TextView whose text should change when the Button is clicked.

Create a new class called MainActivityTests and annotate it with @RunWith(AndroidJUnit4::class). Next, add the function below to launch the MainActivity:

class MainActivityTests {
    fun setup(){

As demonstrated below, Kakao is quite simple to implement. We use the onScreen<> to write our assertions:

onScreen<TestScreen> {

We can now test to see if our first TextView contains the right title and that it is displayed correctly:

fun test_if_title_textview_is_displayed_and_has_correct_title(){
    onScreen<MainScreen> {
        titleTextview.hasText("Testing with Kakao is awesome")

Next, test if the first ImageView contains the right image and it is displayed:

fun test_if_android_image_is_displayed_and_the_right_one(){
    onScreen<MainScreen> {

Check if our first TextView changes texts when the Button is clicked:

fun test_if_text_is_changed_on_button_click(){
    onScreen<MainScreen> {
        changedTextView.hasNoText("Text to be changed")
        changedTextView.hasText("Something else")

Let’s test the second activity that simulates a sign-up form. We will test if the correct errors are shown when fields are left blank.

Create a new test class called RegisterActivityTests. Write the setup function below to launch it.

We use the following code to test if an error is set to the EditText when it is left blank:

fun test_if_email_edittext_when_empty_returns_an_error(){

        emailEditText.replaceText("") // empty text
        nameEditText.replaceText("zf") // random text

            view.check(matches(hasErrorText("Email field cannot be empty")))

You can use the above code to test other EditTexts.

Test to see if a Snackbar is shown when all fields are filled correctly:

fun test_that_a_snackbar_is_shown_when_all_fields_filled(){
        nameEditText.replaceText("John Doe")



Finally, let’s go ahead and write tests for our SearchScreen.

Create a new class named SearchActivityTests. Here, we will see if the Recyclerview displays the correct items and that when we search, our Snackbar displays the respective content.

Testing whether a Snackbar appears when the search EditText is left blank:

fun test_if_search_edittext_is_empty_shows_a_snackbar(){
            hasText("Empty search field")

Testing if the RecyclerView item contains the correct content:

fun first_recylerview_item_has_correct_name_price_and_type(){
    onScreen<SearchScreen> {
        carsRecyclerview {
            firstChild<SearchScreen.Item> {
                name {hasText("Audi")}
                price {hasText("15000000")}
                type {hasText("Q3")}

Testing if the Recyclerview has the correct number of items.

fun test_the_size_of_the_recyclerview_list_is_14(){
    onScreen<SearchScreen> {
        carsRecyclerview {


When you run the tests, they should all pass as shown below unless you have any errors:

test pass


In this tutorial, we have discussed how Kakao outperforms Espresso. We’ve also learned how to integrate Kakao into an Android Project.

Finally, we wrote tests for our user interfaces using Kakao.

You can read more about Kakao for Jetpack Compose Here.

The complete code can be found on this GitHub repository.

Further reading

Happy coding!

Peer Review Contributions by: Eric Gacoki