test: failing regression test for #546 (ignored until fixed): solid.extrude with taper refuses profiles of lines and arcs: "not supported yet: tapered profiles mixing lines and arcs" (#571)

Adds an ignored regression test for #546; it runs once #546 is fixed.

crates/engine/src/tests.rs

@@ -2920,3 +2920,21 @@ fn a_pattern_of_a_reduced_fillet_rounds_each_copy_alike() {
     let expect = 60.0 * 20.0 * 2.0 + 3.0 * (840.0 - (4.0 - PI) * 9.0 * 10.0);
     assert!(rel(volume(&mut s), expect) < 2e-4, "{} vs {expect}", volume(&mut s));
 }
+
+/// A taper on a profile of lines and an arc (#546). The D profile (back 9.2, sides 7.4, a
+/// half-round front R 4.6 tangent to them) grows by d = z · tan 5° with mitred corners:
+/// A(d) = A₀ + P·d + (2 + π/2)·d², integrated over the 10 mm height.
+#[test]
+#[ignore = "fails until #546 is fixed"]
+fn tapered_extrude_of_a_profile_mixing_lines_and_an_arc() {
+    let mut s = Session::default();
+    run(&mut s, "sketch.create", json!({"plane": "XY", "name": "D"}));
+    run(&mut s, "sketch.line", json!({"points": [[0, 4.6], [-7.4, 4.6], [-7.4, -4.6], [0, -4.6]], "closed": false}));
+    run(&mut s, "sketch.arc.center_point", json!({"center": [0, 0], "start": [0, -4.6], "end": [0, 4.6]}));
+    run(&mut s, "sketch.finish", json!({}));
+    run(&mut s, "solid.extrude", json!({"sketch": "D", "distance": 10, "taper": "5 deg"}));
+    let (t, h) = (5f64.to_radians().tan(), 10.0);
+    let (a0, p, k) = (7.4 * 9.2 + PI * 4.6 * 4.6 / 2.0, 2.0 * 7.4 + 9.2 + PI * 4.6, 2.0 + PI / 2.0);
+    let expect = a0 * h + p * t * h * h / 2.0 + k * t * t * h.powi(3) / 3.0;
+    assert!(rel(volume(&mut s), expect) < 1e-3, "{} vs {expect}", volume(&mut s));
+}