fix upd speed waterflow

tests/test_processing.py

@@ -16,9 +16,11 @@ from rfg_adc_plotter.gui.pyqtgraph_backend import (
     compute_background_subtracted_bscan_levels,
     compute_aux_phase_curve,
     convert_tty_i16_to_voltage,
+    decimate_bscan_rows_for_display,
     decimate_curve_for_display,
     is_short_sweep,
     resolve_axis_bounds,
+    resolve_bscan_refresh_stride,
     resolve_heavy_refresh_stride,
     resolve_initial_window_size,
     resolve_distance_cut_start,
@@ -377,6 +379,31 @@ class ProcessingTests(unittest.TestCase):
         self.assertEqual(resolve_heavy_refresh_stride(8, max_packets=8), 2)
         self.assertEqual(resolve_heavy_refresh_stride(16, max_packets=8), 4)
 
+    def test_resolve_bscan_refresh_stride_limits_suppression(self):
+        self.assertEqual(resolve_bscan_refresh_stride(0, max_packets=8), 1)
+        self.assertEqual(resolve_bscan_refresh_stride(8, max_packets=8), 1)
+        self.assertEqual(resolve_bscan_refresh_stride(16, max_packets=8), 2)
+
+    def test_decimate_bscan_rows_for_display_keeps_shape_consistent(self):
+        axis = np.linspace(0.0, 1.0, 10, dtype=np.float64)
+        data = np.arange(50, dtype=np.float32).reshape(10, 5)
+
+        dec_axis, dec_data = decimate_bscan_rows_for_display(axis, data, max_points=4)
+
+        self.assertEqual(dec_data.shape, (4, 5))
+        self.assertIsNotNone(dec_axis)
+        self.assertEqual(dec_axis.shape, (4,))
+        self.assertAlmostEqual(float(dec_axis[0]), 0.0, places=12)
+        self.assertAlmostEqual(float(dec_axis[-1]), 1.0, places=12)
+
+    def test_decimate_bscan_rows_for_display_handles_missing_axis(self):
+        data = np.arange(32, dtype=np.float32).reshape(8, 4)
+
+        dec_axis, dec_data = decimate_bscan_rows_for_display(None, data, max_points=3)
+
+        self.assertIsNone(dec_axis)
+        self.assertEqual(dec_data.shape, (3, 4))
+
     def test_update_expected_sweep_width_initializes_from_first_valid_sweep(self):
         self.assertEqual(update_expected_sweep_width(0, 411), 411)