mobile-testing

Mobile Testing Patterns

Test Dependencies

// build.gradle.kts
dependencies {
    testImplementation(platform("org.junit:junit-bom:6.1.3")) // JUnit 6 / Jupiter 6 — requires Java 17+
    testImplementation("org.junit.jupiter:junit-jupiter")
    testRuntimeOnly("org.junit.platform:junit-platform-launcher") // mandatory since Gradle 9
    testImplementation("io.mockk:mockk:1.14.11")
    testImplementation("app.cash.turbine:turbine:1.2.1")
    testImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.11.0")
    testImplementation("io.kotest:kotest-assertions-core:6.2.4")

    androidTestImplementation(platform("androidx.compose:compose-bom:2026.08.00"))
    androidTestImplementation("androidx.compose.ui:ui-test-junit4")
    debugImplementation("androidx.compose.ui:ui-test-manifest")
}

// Without useJUnitPlatform() the Jupiter tests are never discovered — the task
// reports success with zero tests. This form works in JVM, KMP and AGP modules:
tasks.withType<Test>().configureEach { useJUnitPlatform() }

• androidTestImplementation does not extend implementation, so the Compose BOM must be repeated there; debugImplementation does extend it, so ui-test-manifest inherits the version.
• android { testOptions { unitTests.all { it.useJUnitPlatform() } } } still works under com.android.application/com.android.library. AGP 9 forbids those plugins alongside org.jetbrains.kotlin.multiplatform, and the replacement com.android.kotlin.multiplatform.library plugin has no testOptions DSL — KMP modules need the tasks.withType<Test> form.
• Jupiter and MockK are JVM-only (MockK publishes a jvm variant and nothing else) — declare them in jvmTest/androidUnitTest only. kotlin("test"), Turbine, kotlinx-coroutines-test and kotest-assertions-core are all published for every KMP target, so they belong in commonTest.

ViewModel Testing

viewModelScope dispatches to Dispatchers.Main — replace it in unit tests or every launch crashes. Use a JUnit 5 extension: