diff --git a/tests/test_ui_filter.py b/tests/test_ui_filter.py
new file mode 100644
index 0000000..227a46c
--- /dev/null
+++ b/tests/test_ui_filter.py
@@ -0,0 +1,44 @@
+from __future__ import annotations
+
+from auditui.ui import FilterScreen
+
+
+class DummyEvent:
+    def __init__(self, value: str) -> None:
+        self.value = value
+
+
+class FakeTimer:
+    def __init__(self, callback) -> None:
+        self.callback = callback
+        self.stopped = False
+
+    def stop(self) -> None:
+        self.stopped = True
+
+
+def test_filter_debounce_uses_latest_value(monkeypatch) -> None:
+    seen: list[str] = []
+    timers: list[FakeTimer] = []
+
+    def on_change(value: str) -> None:
+        seen.append(value)
+
+    screen = FilterScreen(on_change=on_change, debounce_seconds=0.2)
+
+    def fake_set_timer(_delay: float, callback):
+        timer = FakeTimer(callback)
+        timers.append(timer)
+        return timer
+
+    monkeypatch.setattr(screen, "set_timer", fake_set_timer)
+
+    screen.on_input_changed(DummyEvent("a"))
+    screen.on_input_changed(DummyEvent("ab"))
+
+    assert len(timers) == 2
+    assert timers[0].stopped is True
+    assert timers[1].stopped is False
+
+    timers[1].callback()
+    assert seen == ["ab"]