diff --git a/lidar_pipeline/tests/test_dtm.py b/lidar_pipeline/tests/test_dtm.py
index 72a2ef1..86db990 100644
--- a/lidar_pipeline/tests/test_dtm.py
+++ b/lidar_pipeline/tests/test_dtm.py
@@ -548,3 +548,22 @@ class TestPureDtm:
         vals = sorted(float(v) for v in arr.flatten())
         assert len(vals) == 4
         assert vals[-1] == 10.0
+
+
+class TestStripLidarExt:
+    def test_copc_laz(self):
+        from lidar_pipeline.dtm import _strip_lidar_ext
+        assert _strip_lidar_ext("LHD_FXX_1000_6881_PTS_LAMB93_IGN69.copc.laz") == "LHD_FXX_1000_6881_PTS_LAMB93_IGN69"
+
+    def test_laz(self):
+        from lidar_pipeline.dtm import _strip_lidar_ext
+        assert _strip_lidar_ext("file.laz") == "file"
+
+    def test_las(self):
+        from lidar_pipeline.dtm import _strip_lidar_ext
+        assert _strip_lidar_ext("file.las") == "file"
+
+    def test_path_object(self):
+        from lidar_pipeline.dtm import _strip_lidar_ext
+        from pathlib import Path
+        assert _strip_lidar_ext(Path("/data/input/file.copc.laz")) == "file"
diff --git a/lidar_pipeline/tests/test_visualizations.py b/lidar_pipeline/tests/test_visualizations.py
index 0af1a43..7e0319d 100644
--- a/lidar_pipeline/tests/test_visualizations.py
+++ b/lidar_pipeline/tests/test_visualizations.py
@@ -326,3 +326,44 @@ def test_ray_trace_horizons_reraises_non_oom(monkeypatch):
         assert False, "ValueError attendue"
     except ValueError:
         pass
+
+
+class TestPriorityFlood:
+    def test_numba_matches_python(self):
+        """Le résultat numba et python sont identiques sur un DEM avec un puits."""
+        from lidar_pipeline.visualizations import _priority_flood_numba, _priority_flood_python
+
+        dem = np.zeros((20, 20), dtype=np.float64)
+        dem[10, 10] = -5.0
+        dem[9:12, 9:12] = -3.0
+        nodata = np.zeros((20, 20), dtype=bool)
+
+        result_numba = _priority_flood_numba(dem.copy(), nodata)
+        result_python = _priority_flood_python(dem.copy(), nodata)
+
+        if result_numba is not None:
+            assert np.allclose(result_numba, result_python)
+
+    def test_pit_is_filled(self):
+        """Un puits isolé est ramené au niveau de son bord."""
+        from lidar_pipeline.visualizations import _priority_flood
+
+        dem = np.full((10, 10), 5.0, dtype=np.float64)
+        dem[5, 5] = 1.0
+        nodata = np.zeros((10, 10), dtype=bool)
+
+        result = _priority_flood(dem, nodata)
+        assert result[5, 5] == 5.0
+
+    def test_nodata_cells_untouched(self):
+        """Les cellules nodata ne sont jamais modifiées."""
+        from lidar_pipeline.visualizations import _priority_flood
+
+        dem = np.full((10, 10), 5.0, dtype=np.float64)
+        dem[5, 5] = 1.0
+        nodata = np.zeros((10, 10), dtype=bool)
+        nodata[2, 2] = True
+        dem[2, 2] = 999.0
+
+        result = _priority_flood(dem, nodata)
+        assert result[2, 2] == 999.0