work on straighten path

tests/node_tests/straighten_path.py

@@ -8,10 +8,11 @@ def test_basic_extraction():
 
     node = StraightenPath()
     field = make_field(shape=(64, 64))
-    (result,) = node.process(field, points_x="0.25, 0.5, 0.75",
-                             points_y="0.5, 0.3, 0.5",
-                             thickness=1, n_samples=256)
+    result, profile = node.process(field, points_x="0.25, 0.5, 0.75",
+                                   points_y="0.5, 0.3, 0.5",
+                                   thickness=1, n_samples=256)
     assert result.data.shape[1] == 256, f"Output width should be n_samples=256, got {result.data.shape[1]}"
+    assert profile.data.shape == (256,)
 
 
 def test_thickness():
@@ -19,10 +20,14 @@ def test_thickness():
 
     node = StraightenPath()
     field = make_field(shape=(64, 64))
-    (result,) = node.process(field, points_x="0.2, 0.8",
-                             points_y="0.5, 0.5",
-                             thickness=5, n_samples=100)
+    result, profile = node.process(field, points_x="0.2, 0.8",
+                                   points_y="0.5, 0.5",
+                                   thickness=5, n_samples=100)
     assert result.data.shape[0] == 5, f"Output height should be thickness=5, got {result.data.shape[0]}"
+    # Profile is the 1-pixel-wide centerline regardless of thickness.
+    assert profile.data.shape == (100,)
+    # For a horizontal line, the centerline equals the middle row of the strip.
+    assert np.allclose(profile.data, result.data[2])
 
 
 def test_single_point_returns_input():
@@ -30,8 +35,33 @@ def test_single_point_returns_input():
 
     node = StraightenPath()
     field = make_field(shape=(64, 64))
-    (result,) = node.process(field, points_x="0.5",
-                             points_y="0.5",
-                             thickness=1, n_samples=100)
-    # With only 1 point, node returns the original field unchanged
+    result, profile = node.process(field, points_x="0.5",
+                                   points_y="0.5",
+                                   thickness=1, n_samples=100)
+    # With only 1 point, node returns the original field unchanged + empty profile.
     assert np.array_equal(result.data, field.data)
+    assert profile.data.shape == (0,)
+
+
+def test_emits_overlay_with_points_and_thickness():
+    from backend.execution_context import active_node, execution_callbacks
+    from backend.nodes.straighten_path import StraightenPath
+
+    node = StraightenPath()
+    field = make_field(shape=(64, 64))
+
+    overlays = []
+    with execution_callbacks(overlay=lambda nid, d: overlays.append(d)), active_node("test"):
+        node.process(field, points_x="0.25, 0.5, 0.75",
+                     points_y="0.5, 0.3, 0.5",
+                     thickness=4, n_samples=128)
+
+    assert len(overlays) == 1
+    ov = overlays[0]
+    assert ov["kind"] == "straighten_path"
+    assert ov["section_title"] == "Path"
+    assert ov["image"].startswith("data:image/png;base64,")
+    assert ov["thickness"] == 4
+    assert ov["xres"] == 64 and ov["yres"] == 64
+    assert [p["x"] for p in ov["points"]] == [0.25, 0.5, 0.75]
+    assert [p["y"] for p in ov["points"]] == [0.5, 0.3, 0.5]