Ensure spawn order is consistent

crates/lb/tests/task.lua

@@ -45,6 +45,26 @@ describe("spawn", function()
     end, 5, 4, nil, 3, nil):await())
     assert(res.n == 3 and res[1] == 1 and res[2] == 3 and res[3] == nil)
   end)
+
+  test("order is consistent", function()
+    -- all tasks spawned in one batch should be resumed in the spawn order
+    local tasks, nums = {}, {}
+    for i = 1, 10 do
+      table.insert(
+        tasks,
+        spawn(function()
+          table.insert(nums, i)
+        end)
+      )
+    end
+    for i = 10, 1, -1 do
+      tasks[i]:await()
+    end
+    assert(#nums == 10)
+    for i = 1, 10 do
+      assert(nums[i] == i)
+    end
+  end)
 end)
 
 describe("sleep", function()