If you are reading this, you probably already love Kotlin for its conciseness and power. You use data classes , when expressions, and extension functions daily. But when it comes to testing that code, do you feel like you are still living in the past? Are you writing tests that look like Java 6?
@Test fun `fetchUser returns data after network call`() = runTest { val client = ApiClient() // This virtual time will skip the delay instantly. val user = client.fetchUser("123") assertEquals("John Doe", user.name) } } curso de testing kotlin
Did you find this "curso" useful? Share your biggest testing pain point in the comments below! If you are reading this, you probably already
@Test fun `adding 2 and 3 should return 5`() { val result = Calculator().add(2, 3) assertEquals(5, result) // Or even nicer: assertNotNull(result) } } Are you writing tests that look like Java 6
Kotest will automatically generate 1000 random pairs of integers (including negative, zero, positive) and run the test. If it fails, it the input to the smallest failing case. Module 6: Testing Flows & SharedFlows Testing StateFlow and SharedFlow requires collecting values in a controlled way. Use TestCollector or launchIn .
result.shouldBe(200) list.shouldContain("Kotlin") exception.shouldThrow<IllegalArgumentException> Kotlin Coroutines are amazing for production, but they are a nightmare for testing if you don't know the tricks. A naive test will pass when it should fail because the coroutine hasn't finished yet. The Golden Rule: runTest Never use Thread.sleep() in tests. Use kotlinx-coroutines-test .
// Real code class ApiClient { suspend fun fetchUser(id: String): User { delay(3000) // Simulate network return User("John Doe") } }
