Testing async tasks

General Usage
1

Consider the following example:

using Test

function fail(fail::Bool)
	@test !fail
end

@testset "task_good" begin
	task = @async fail(false)
	fetch(task)
end

@testset "task_bad" begin
	task = @async fail(true)
	fetch(task)
end

While “task_bad” will correctly fail the test, “task_good” will succeed, with the test summary saying it did not run any tests. I suppose this is expected behaviour. Now this example:

function fail(fail::Bool)
	@testset "task" begin
		@test !fail
	end
end

task1 = @async fail(false)
task2 = @async fail(true)

fetch(task1)
fetch(task2)

would print the results correctly, except it will (understandably) intermix your two independent reports wildly. Now in this simple example, one could synchronize the two tests and one would be fine. But what if I have two tasks that are not independent from each other? Consider something like this:

c = Channel{Nothing}(1)

function fail1(fail::Bool)
	@testset "task" begin
		@test true
		put!(c, nothing)
		@test !fail
	end
end

function fail2(fail::Bool)
	@testset "task" begin
		@test true
		take!(c)
		@test !fail
	end
end

task1 = @async fail1(false)
task2 = @async fail2(true)

fetch(task2)
fetch(task1)

Now I obviously cannot run the two testsets independently. Surely, I can go back to something like the first version:

c = Channel{Nothing}(1)

function fail1(fail::Bool)
	@test true
	put!(c, nothing)
	@test !fail
end

function fail2(fail::Bool)
	@test true
	take!(c)
	@test !fail
end

@testset "task_good" begin
	task1 = @async fail1(false)
	task2 = @async fail2(false)
	fetch(task2)
	fetch(task1)
end

@testset "task_bad" begin
	task1 = @async fail1(true)
	task2 = @async fail2(true)
	fetch(task2)
	fetch(task1)
end

but then, “task_good” will again succeed with “No tests”. So my question is: is this something I have to live with, or is there some other way to test non-independent-tasks scenarios?

2

I ran into the same issue.
How did you handle this problem?