kotlin-testing

Choose a Kotest spec style like FunSpec, create mocks with mockk<Repository>(), stub calls with every or coEvery for suspend functions, and assert with matchers like shouldBe. Verify interactions using verify or coVerify.

Wrap test bodies in runTest from kotlinx-coroutines-test, use coEvery and coVerify from MockK for suspend mocks, and control virtual time with advanceTimeBy instead of Thread.sleep. TestDispatcher gives controlled execution of launched coroutines.

StringSpec suits simple assertions, FunSpec mirrors JUnit-style tests, BehaviorSpec fits BDD Given/When/Then scenarios, and DescribeSpec matches RSpec-style nesting. Pick one style and apply it consistently across the project.

Yes, Kotest property testing uses forAll and checkAll with Arb generators to verify invariants across random inputs. Build custom generators with Arb.bind to produce domain objects like User or Money for roundtrip and idempotency checks.

Apply the kotlinx.kover Gradle plugin and add a verify rule with minBound(80) in the kover reports block. Run ./gradlew koverVerify to fail the build below the threshold and koverHtmlReport to inspect results.

Data classes are simple value holders, so use real instances as test fixtures instead of mocks. Mocking them adds fragility without benefit; reserve MockK for services, repositories, and other behavioral dependencies.