Add a check that there are no running workers at end of the tests (#127)

Author: giordano

test/runtests.jl

@@ -802,4 +802,13 @@ end
     @test contains(str, "SUCCESS")
 end
 
+# This testset should always be the last one, don't add anything after this.
+# We want to make sure there are no running workers at the end of the tests.
+@testset "no workers running" begin
+    children = _count_child_pids()
+    if children >= 0
+        @test children == 0
+    end
+end
+
 end