tui: "backpressure": Drop messages to avoid flooding.

Closes #1234

multiqueue:
- Implement multiqueue_size()
- Rename MultiQueueItem.parent to MultiQueueItem.parent_item, to avoid confusion
  with MultiQueue.parent.

1 files changed, 21 insertions, 0 deletions

diff --git a/test/unit/queue_spec.lua b/test/unit/multiqueue_spec.lua
index d802367835..c7f8dd8328 100644
--- a/test/unit/queue_spec.lua
+++ b/test/unit/multiqueue_spec.lua
@@ -36,6 +36,27 @@ describe("multiqueue (multi-level event-queue)", function()
     put(child3, 'c3i2')
   end)
 
+  it('keeps count of added events', function()
+    eq(3, multiqueue.multiqueue_size(child1))
+    eq(4, multiqueue.multiqueue_size(child2))
+    eq(2, multiqueue.multiqueue_size(child3))
+  end)
+
+  it('keeps count of removed events', function()
+    multiqueue.multiqueue_get(child1)
+    eq(2, multiqueue.multiqueue_size(child1))
+    multiqueue.multiqueue_get(child1)
+    eq(1, multiqueue.multiqueue_size(child1))
+    multiqueue.multiqueue_get(child1)
+    eq(0, multiqueue.multiqueue_size(child1))
+    put(child1, 'c2ixx')
+    eq(1, multiqueue.multiqueue_size(child1))
+    multiqueue.multiqueue_get(child1)
+    eq(0, multiqueue.multiqueue_size(child1))
+    multiqueue.multiqueue_get(child1)
+    eq(0, multiqueue.multiqueue_size(child1))
+  end)
+
   it('removing from parent removes from child', function()
     eq('c1i1', get(parent))
     eq('c1i2', get(parent))