Testing Compose Multiplatform UI

Create the test source set and add the testing library to dependencies

To provide concrete examples, the instructions on this page follow the project structure generated by the Kotlin Multiplatform wizard. If you are adding tests to an existing project, you may have to replace composeApp in paths and commands with the module name you are testing (shared, for example).

Create a common test source set and add the necessary dependencies:

1. Create a directory for the common test source set: composeApp/src/commonTest/kotlin.

2. In the composeApp/build.gradle.kts file, add the following dependencies:

   kotlin {
       //...
       sourceSets {
           val desktopTest by getting
   
           // Adds common test dependencies
           commonTest.dependencies {
               implementation(kotlin("test"))
   
               @OptIn(org.jetbrains.compose.ExperimentalComposeLibrary::class)
               implementation(compose.uiTest)
           }
   
           // Adds the desktop test dependency
           desktopTest.dependencies {
               implementation(compose.desktop.currentOs)
           }
       }
   }

3. If you need to run instrumented (emulator) tests for Android, amend your Gradle configuration further:

   1. Add the following code to the androidTarget {} block and follow IDE's suggestions to add missing imports:

      kotlin {
          //...
          androidTarget {
              @OptIn(ExperimentalKotlinGradlePluginApi::class)
              instrumentedTestVariant.sourceSetTree.set(KotlinSourceSetTree.test)
              //...
          }
          //...
      }

   2. Add the following code to the android.defaultConfig {} block:

      android {
          //...
          defaultConfig {
              //...
              testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
          }
      }

   3. Add the following code to the config top level:

      //https://developer.android.com/develop/ui/compose/testing#setup
      dependencies {
          androidTestImplementation("androidx.compose.ui:ui-test-junit4-android:1.6.8")
          debugImplementation("androidx.compose.ui:ui-test-manifest:1.6.8")
      }

Now, you are ready to write and run common tests for the Compose Multiplatform UI.

Write and run common tests

In the composeApp/src/commonTest/kotlin directory, create a file named ExampleTest.kt and copy the following code into it:

import androidx.compose.material.*
import androidx.compose.runtime.*
import androidx.compose.ui.Modifier
import androidx.compose.ui.platform.testTag
import androidx.compose.ui.test.*
import kotlin.test.Test

class ExampleTest {

    @OptIn(ExperimentalTestApi::class)
    @Test
    fun myTest() = runComposeUiTest {
        // Declares a mock UI to demonstrate API calls
        //
        // Replace with your own declarations to test the code of your project
        setContent {
            var text by remember { mutableStateOf("Hello") }
            Text(
                text = text,
                modifier = Modifier.testTag("text")
            )
            Button(
                onClick = { text = "Compose" },
                modifier = Modifier.testTag("button")
            ) {
                Text("Click me")
            }
        }

        // Tests the declared UI with assertions and actions of the Compose Multiplatform testing API
        onNodeWithTag("text").assertTextEquals("Hello")
        onNodeWithTag("button").performClick()
        onNodeWithTag("text").assertTextEquals("Compose")
    }
}

To run tests:

./gradlew :composeApp:connectedAndroidTest

./gradlew :composeApp:wasmJsTest