Tests: a round wall is one face, its name without a piece number

Since 09c979a4b a circle is one closed arc, so an extruded circle's wall, a hole's wall and a
cylinder's side are one face each, closed along a seam. Tests that counted truck's two halves:
- certified_annulus_side_rows_follow_radius_edits_and_clone and
  certified_side_transfer_preserves_geometry_and_unsupported_taper_refuses_atomically: the
  painted outer wall is 1 face (every vertex of it still at the painted radius), not 2;
- offset_surface_of_a_cylinder_and_a_box_top: the offset sleeve is 1 face (its area 2π·12·20
  unchanged);
- press_pull_then_curved_face_offsets_it: a click on the hole's wall offsets its 1 face;
- pi_case_faces_per_step_at_both_heights: each standoff (a ring, Ø6 round a Ø2.5 hole) adds 4
  faces, not 6: its outer and inner wall, its top, the floor inside its hole. So 23 after the
  first and 35 after the pattern of four; the port openings (3 × 4), the end cut-out (4) and the
  five vents (5 × 4) are planar and add what they did: 47, 51, 55, 71.
- the_round_sides_of_a_thin_ring_are_named_by_the_circle_they_run_beside: a thin ring 2 thick
  about the R10 circle has two walls, `F2:wall:c1:left` (radius 9: the counter-clockwise
  circle's left is inside) and `F2:wall:c1:right` (radius 11), with no numbers; each name is
  found again by a point on its own wall.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/cmd/config_certificate_tests.rs

@@ -49,22 +49,22 @@ fn certified_annulus_side_rows_follow_radius_edits_and_clone() {
     run(&mut s, "sketch.finish", json!({}));
     run(&mut s, "solid.extrude", json!({"distance":10,"profiles":[{"point":[9.5,0]}],"body_name":"Ring"}));
     paint(&mut s, "Ring", json!([10, 0, 5]));
-    assert_eq!(painted_radius(&s, "Ring", 10.), 2, "both constructed arc pieces share outer curve");
+    assert_eq!(painted_radius(&s, "Ring", 10.), 1, "the outer circle's wall is one face, closed along its seam");
     let Column::FaceAppearance(target) = &s.doc.configs.columns[0] else { panic!() };
     assert_eq!(target.certificate, Some(FaceCertificate::ExtrudeSide { sketch, curve: "outer".into() }));
     run(&mut s, "parameters.change", json!({"name":dimensions[0],"expression":"12 mm"}));
     run(&mut s, "parameters.change", json!({"name":dimensions[1],"expression":"9.25 mm"}));
     run(&mut s, "config.activate", json!({"row":"Painted"}));
-    assert_eq!(painted_radius(&s, "Ring", 12.), 2);
+    assert_eq!(painted_radius(&s, "Ring", 12.), 1);
     run(&mut s, "component.paste_new", json!({"component":part,"translate":[30,0,0]}));
     assert_eq!(s.doc.configs.columns.len(), 2);
     run(&mut s, "config.activate", json!({"row":"Painted"}));
-    assert_eq!(painted_radius(&s, "Ring (2)", 12.), 2);
+    assert_eq!(painted_radius(&s, "Ring (2)", 12.), 1);
     let reopened = solidcraft_doc::Document::from_json(&s.doc.to_json()).unwrap();
     let mut reopened = Session::new(reopened);
     run(&mut reopened, "config.activate", json!({"row":"Painted"}));
-    assert_eq!(painted_radius(&reopened, "Ring", 12.), 2);
-    assert_eq!(painted_radius(&reopened, "Ring (2)", 12.), 2);
+    assert_eq!(painted_radius(&reopened, "Ring", 12.), 1);
+    assert_eq!(painted_radius(&reopened, "Ring (2)", 12.), 1);
     run(&mut reopened, "config.activate", json!({"row":"Default"}));
     assert!(reopened.doc.appearances.faces.is_empty());
 }
@@ -227,11 +227,11 @@ fn certified_side_transfer_preserves_geometry_and_unsupported_taper_refuses_atom
     run(&mut s, "occurrence.move", json!({"occurrence":occurrence,"translate":[30,20,0],"angle":90,"axis":[0,0,1],"capture":false}));
     run(&mut s, "component.move_bodies", json!({"component":destination,"bodies":["Round"]}));
     run(&mut s, "config.activate", json!({"row":"Painted"}));
-    assert_eq!(painted_radius(&s, "Round", 10.), 2);
+    assert_eq!(painted_radius(&s, "Round", 10.), 1);
     let before = s.world_state().unwrap().body("Round").unwrap().mesh().bounds();
     let mut s = Session::new(solidcraft_doc::Document::from_json(&s.doc.to_json()).unwrap());
     run(&mut s, "config.activate", json!({"row":"Painted"}));
-    assert_eq!(painted_radius(&s, "Round", 10.), 2);
+    assert_eq!(painted_radius(&s, "Round", 10.), 1);
     assert!(
         s.world_state().unwrap().body("Round").unwrap().mesh().bounds().min.dist(before.min) < 1e-8,
         "before {before:?}, reopened {:?}",

crates/engine/src/cmd/surface.rs

@@ -1091,9 +1091,9 @@ mod tests {
         }
     }
 
-    /// Offset Surface: a cylinder's side picked once with its chain (both halves) moved out to
-    /// radius 12; a box top moved up exactly; a zero distance copies; past the axis refused, the
-    /// design left as it was; undo, redo and reopening.
+    /// Offset Surface: a cylinder's side (one face, closed along its seam) picked with its chain
+    /// moved out to radius 12; a box top moved up exactly; a zero distance copies; past the axis
+    /// refused, the design left as it was; undo, redo and reopening.
     #[test]
     fn offset_surface_of_a_cylinder_and_a_box_top() {
         let mut s = Session::default();
@@ -1101,7 +1101,7 @@ mod tests {
         run(&mut s, "surface.offset", json!({"faces": [[10, 0, 10]], "chain": true, "distance": 2, "body": "Can", "body_name": "Sleeve"}));
         let st = s.world_state().unwrap();
         let sleeve = &st.body("Sleeve").unwrap().body;
-        assert!(sleeve.is_surface() && sleeve.face_count() == 2);
+        assert!(sleeve.is_surface() && sleeve.face_count() == 1);
         let want = 2.0 * std::f64::consts::PI * 12.0 * 20.0;
         assert!((area(&s, "Sleeve") - want).abs() < want * 1e-3, "{} vs {want}", area(&s, "Sleeve")); // (measured on meshes)
         assert!(st.body("Can").is_some(), "the source body stays");

crates/engine/src/cmd/thin_extrude_tests.rs

@@ -371,10 +371,15 @@ fn the_round_sides_of_a_thin_ring_are_named_by_the_circle_they_run_beside() {
     run(&mut s, "solid.extrude", json!({"sketch": "Outline", "thin": true, "thickness": 2, "distance": 5, "name": "Ring"}));
     let world = s.world_state().unwrap();
     let names = solidcraft_doc::naming::face_names(world.bodies.first().unwrap());
-    // Each round side is two half cylinders, told apart by their numbers.
+    // Each round side is one cylinder, closed along its seam, so its name needs no number.
     let walls: Vec<_> = names.iter().filter(|name| name.contains(":wall:")).collect();
-    assert_eq!(walls.len(), 4, "{names:?}");
-    for side in ["left", "right"] {
-        assert_eq!(walls.iter().filter(|name| name.contains(&format!(":wall:c1:{side}#"))).count(), 2, "{walls:?}");
+    assert_eq!(walls.len(), 2, "{names:?}");
+    // The wall is 2 thick about the circle (radius 9 to 11). The circle runs counter-clockwise,
+    // so its left is the inner side; each name is found again at a point on its own wall.
+    for (side, radius) in [("left", 9.0), ("right", 11.0)] {
+        let name = format!("F2:wall:c1:{side}");
+        assert!(walls.contains(&&name), "{walls:?}");
+        let at = solidcraft_geom::Vec3::new(0.0, radius, 2.5);
+        assert_eq!(solidcraft_doc::naming::face_names_at(&s.model.state(), &[at]), vec![name.clone()]);
     }
 }