Curso De Testing Kotlin -

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 .

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 {

class MathProps : StringSpec({ "Addition should be commutative" { forAll { a: Int, b: Int -> // The property we want to test (a + b) == (b + a) } } "String length should be non-negative" { forAll<Int> { length -> val str = "x".repeat(length.coerceAtLeast(0)) str.length >= 0 } } }) curso de testing kotlin

@Test fun `adding 2 and 3 should return 5`() { val result = Calculator().add(2, 3) assertEquals(5, result) // Or even nicer: assertNotNull(result) } }

@Test fun `verify API is called only once`() = runTest { // 1. Create mock val api = mockk<MyApi>() // 2. Stub a suspend function (coEvery) coEvery { api.getData() } returns "Mocked Response" val repo = Repository(api) // 3. Execute val result = repo.refreshData() // 4. Verify (coVerify) coVerify(exactly = 1) { api.getData() } result shouldBe "Mocked Response" } } Traditional testing (Example-based) says: "Give input 2+2, check output 4." Property-based testing says: "For ALL integers, addition should be commutative." Kotest will automatically generate 1000 random pairs of

@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) } }

Did you find this "curso" useful? Share your biggest testing pain point in the comments below! Use TestCollector or launchIn

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?