some fixes

python_app/tests/test_log_panel_buffer.py

@@ -0,0 +1,48 @@
+"""Unit tests for the bounded GUI log-panel buffer.
+
+The buffer decouples logging handlers (any thread, potentially very chatty at
+DEBUG) from the GUI: records are batched by a flush timer instead of posting one
+queued Qt event per record, and overflow drops the oldest records with a count.
+"""
+
+from __future__ import annotations
+
+import unittest
+
+from python_app.gui.app_window import _PanelLogBuffer
+
+
+class PanelLogBufferTest(unittest.TestCase):
+    """Bounded capacity, oldest-first eviction, and accurate drop accounting."""
+
+    def test_drain_returns_entries_in_order_and_clears(self) -> None:
+        buffer = _PanelLogBuffer()
+        buffer.append("INFO", "first", None, None)
+        buffer.append("WARN", "second", "details", "key")
+
+        entries, dropped_count = buffer.drain()
+
+        self.assertEqual(dropped_count, 0)
+        self.assertEqual(
+            entries,
+            [("INFO", "first", None, None), ("WARN", "second", "details", "key")],
+        )
+        self.assertEqual(buffer.drain(), ([], 0))
+
+    def test_overflow_drops_oldest_and_counts(self) -> None:
+        buffer = _PanelLogBuffer()
+        overflow = 100
+        total = _PanelLogBuffer._CAPACITY + overflow
+        for index in range(total):
+            buffer.append("DEBUG", f"m{index}", None, None)
+
+        entries, dropped_count = buffer.drain()
+
+        self.assertEqual(dropped_count, overflow)
+        self.assertEqual(len(entries), _PanelLogBuffer._CAPACITY)
+        self.assertEqual(entries[0][1], f"m{overflow}")
+        self.assertEqual(entries[-1][1], f"m{total - 1}")
+
+
+if __name__ == "__main__":
+    unittest.main()