Testing for asynchronous results without sleep in Go

Question

I have quite a few components in my code that have persistent go-routines that listen for events to trigger actions. Most of the time, there is no reason (outside of testing) fo

Answer 1

The idiomatic way is to pass a done channel along with your data to the worker go-routine. The go-routine should close the done channel and your code should wait until the channel is closed:

done := make(chan bool)

// Send notification event.
mock.devices <- Job {
    Data: []sparkapi.Device{deviceA, deviceFuncs, deviceRefresh},
    Done: done,
}

// Wait until `done` is closed.
<-done

// Check that no refresh method was called.
c.Check(mock.actionArgs, check.DeepEquals, mockFunctionCall{})

Using this pattern, you can also implement a timeout for your test:

// Wait until `done` is closed.
select {
case <-done:
case <-time.After(10 * time.Second):
    panic("timeout")
}