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Handler Validation

MediatorK ships a companion test utilities artifact — mediatork-test — that helps you catch missing handler registrations at test time instead of as a runtime crash.

assertAllHandlersRegistered​

MediatorTestUtils.assertAllHandlersRegistered scans the classpath for every concrete RequestHandler implementation and asserts that each one is wired up via your registrars.

If a handler exists but was forgotten in a MediatorRegistrar, the test fails immediately with a clear message instead of crashing at runtime when the request is first dispatched.

Basic usage​

Scan the entire classpath — simplest setup, works for most projects:

import com.fajrbahr.mediatork.test.MediatorTestUtils
import kotlin.test.Test

class HandlerCoverageTest {

    @Test
    fun `all handlers are registered`() {
        MediatorTestUtils.assertAllHandlersRegistered(
            registrars = listOf(
                OrderRegistrar(),
                UserRegistrar(),
            ),
        )
    }
}

Narrow the scan to specific packages​

If third-party libraries on your classpath also implement RequestHandler, scanning everything may produce false positives. Pass packages to restrict the scan:

MediatorTestUtils.assertAllHandlersRegistered(
    registrars = listOf(
        OrderRegistrar(),
        UserRegistrar(),
    ),
    packages = listOf("com.myapp.order", "com.myapp.user"),
)

Failure message​

When a handler is missing the test fails with a descriptive message:

Unregistered handlers found:
  - CreateOrderHandler handles CreateOrderCommand — not registered
  - FetchUserHandler handles FetchUserQuery — not registered

Parameters​

ParameterTypeDefaultDescription
registrarsList<MediatorRegistrar>—The same registrars you pass to MediatorFactory.create.
packagesList<String>emptyList()Packages to scan. Empty list scans the entire classpath.