hobby: Fix closed two point hobby curve (#468)

Fixes #462.

src/hobby.typ

@@ -271,7 +271,7 @@
  assert(omega.all(x => x >= 0),
  message: "Omega must contain positive values only")
 
- if points.len() == 2 {
+ if not close and points.len() == 2 {
  let (a, b) = points
  return ((a, b, a, b),)
  }

tests/hobby/test.typ

@@ -1,27 +1,35 @@
 #set page(width: auto, height: auto)
 #import "/src/lib.typ": *
+#import "/tests/helper.typ": *
 
-#box(stroke: 2pt + red, canvas({
- import draw: *
- hobby((0,0), (1,0))
-}))
-
-#box(stroke: 2pt + red, canvas({
+#test-case({
  import draw: *
  hobby((0,-1), (1,1), (2,0), (3,1), (4,0), (5,2), omega: 0)
-}))
+})
 
-#box(stroke: 2pt + red, canvas({
+#test-case({
  import draw: *
  hobby((0,-1), (1,1), (2,0), (3,1), (4,0), (5,2), omega: .5)
-}))
+})
 
-#box(stroke: 2pt + red, canvas({
+#test-case({
  import draw: *
  hobby((0,-1), (1,1), (2,0), (3,1), (4,0), (5,2), omega: 1)
-}))
+})
 
-#box(stroke: 2pt + red, canvas({
+#test-case({
  import draw: *
  hobby((0,-1), (1,1), (2,0), (3,1), (4,0), (5,2), close: true, fill: blue)
-}))
+})
+
+// Two points, not closed
+#test-case({
+ import draw: *
+ hobby((0,0), (1,1))
+})
+
+// Two points, closed
+#test-case({
+ import draw: *
+ hobby((0,0), (1,1), close: true)
+})