Whether you are building Android apps, backend services with Ktor or Spring Boot, or multi-platform libraries, Kotlin offers a unique set of tools to make testing not just bearable , but joyful .
Use TestDispatcher and advanceUntilIdle() to control time precisely. Module 4: Mocking with MockK (Not Mockito) If you come from Java, you know Mockito. For Kotlin, you need MockK . Why? Because Mockito fails when dealing with final classes (Kotlin classes are final by default) and suspend functions. Mocking a suspend function import io.mockk.coEvery import io.mockk.coVerify import io.mockk.mockk class RepositoryTest { curso de testing kotlin
src/ test/kotlin/ # Unit tests (run fast, no Android/Server) integrationTest/ # Integration tests (use real DB) testFixtures/ # Shared test data (factories, builders) Whether you are building Android apps, backend services
In this guide, we will move from basic JUnit setup to advanced property-based testing and coroutine simulation. Forget the old @Test annotations that feel clunky. Kotlin allows us to write tests that read like plain English. The Setup (Gradle) // build.gradle.kts dependencies { testImplementation("org.junit.jupiter:junit-jupiter:5.10.0") testImplementation("org.jetbrains.kotlin:kotlin-test-junit5") } The First Test: Clean Syntax Notice how we avoid assertThat(actual).isEqualTo(expected) (Hamcrest) or Assert.assertEquals() (JUnit). Instead, we use Kotlin's infix functions via the kotlin.test library. For Kotlin, you need MockK