new background remove algoritm

tests/test_background_buffer.py

@@ -0,0 +1,44 @@
+from __future__ import annotations
+
+import numpy as np
+import unittest
+
+from rfg_adc_plotter.state.background_buffer import BackgroundMedianBuffer
+
+
+class BackgroundMedianBufferTests(unittest.TestCase):
+    def test_buffer_returns_median_for_partial_fill(self):
+        buffer = BackgroundMedianBuffer(max_rows=4)
+        buffer.push(np.asarray([1.0, 5.0, 9.0], dtype=np.float32))
+        buffer.push(np.asarray([3.0, 7.0, 11.0], dtype=np.float32))
+
+        median = buffer.median()
+
+        self.assertIsNotNone(median)
+        self.assertTrue(np.allclose(median, np.asarray([2.0, 6.0, 10.0], dtype=np.float32)))
+
+    def test_buffer_wraparound_keeps_latest_rows(self):
+        buffer = BackgroundMedianBuffer(max_rows=2)
+        buffer.push(np.asarray([1.0, 5.0], dtype=np.float32))
+        buffer.push(np.asarray([3.0, 7.0], dtype=np.float32))
+        buffer.push(np.asarray([9.0, 11.0], dtype=np.float32))
+
+        median = buffer.median()
+
+        self.assertIsNotNone(median)
+        self.assertTrue(np.allclose(median, np.asarray([6.0, 9.0], dtype=np.float32)))
+
+    def test_buffer_reset_clears_state(self):
+        buffer = BackgroundMedianBuffer(max_rows=2)
+        buffer.push(np.asarray([1.0, 2.0], dtype=np.float32))
+
+        buffer.reset()
+
+        self.assertIsNone(buffer.rows)
+        self.assertIsNone(buffer.median())
+        self.assertEqual(buffer.count, 0)
+        self.assertEqual(buffer.head, 0)
+
+
+if __name__ == "__main__":
+    unittest.main()