``` data class Event(val msg: String) ...

# mockk

[oleksiyp]

data class Event(val msg: String)

        class A {
            val channels = mutableMapOf<String, Channel<Event>>()

            fun getB(c: String) = channels.getOrPut(c) { Channel() }
        }

        val a = mockk<A>()

        coEvery {
            val ch = a.getB(any())
            ch.send(any())
        } just Runs

        runBlocking { a.getB("abc").send(Event("def")) }