test the gc queue is not empty while gil still unlocked

Author: Christopher Doris

test/GC.jl

@@ -1,23 +1,27 @@
 @testitem "GC.gc()" begin
     let
         pyobjs = map(pylist, 1:100)
-        PythonCall.GIL.@unlock Threads.@threads for obj in pyobjs
-            finalize(obj)
+        PythonCall.GIL.@unlock begin
+            Threads.@threads for obj in pyobjs
+                finalize(obj)
+            end
+            Threads.nthreads() > 1 && @test !isempty(PythonCall.GC.QUEUE.items)
         end
     end
-    Threads.nthreads() > 1 && @test !isempty(PythonCall.GC.QUEUE.items)
     PythonCall.GC.gc()
     @test isempty(PythonCall.GC.QUEUE.items)
 end
 
 @testitem "GC.GCHook" begin
     let
         pyobjs = map(pylist, 1:100)
-        PythonCall.GIL.@unlock Threads.@threads for obj in pyobjs
-            finalize(obj)
+        PythonCall.GIL.@unlock begin
+            Threads.@threads for obj in pyobjs
+                finalize(obj)
+            end
+            Threads.nthreads() > 1 && @test !isempty(PythonCall.GC.QUEUE.items)
         end
     end
-    Threads.nthreads() > 1 && @test !isempty(PythonCall.GC.QUEUE.items)
     GC.gc()
     @test isempty(PythonCall.GC.QUEUE.items)
 end