tests: Add tests for custom marks

tests/mark/custom/test.typ

@@ -0,0 +1,42 @@
+#import "/src/lib.typ": *
+#import "/tests/helper.typ": *
+#set page(width: auto, height: auto)
+
+#let register-face() = {
+  import draw: *
+
+  register-mark("face", style => {
+    circle((0,0), radius: .5, fill: yellow)
+    arc((0,0), start: 180deg + 30deg, delta: 180deg - 60deg, anchor: "origin", radius: .3)
+    circle((-.15, +.15), radius: .1, fill: white)
+    circle((-.10, +.10), radius: .025, fill: black)
+    circle((+.15, +.15), radius: .1, fill: white)
+    circle((+.20, +.10), radius: .025, fill: black)
+
+    anchor("tip", (+.5, 0))
+    anchor("base", (-.5, 0))
+  }, mnemonic: ":)")
+}
+
+#test-case({
+  import draw: *
+
+  register-face()
+  catmull((-3, 0), (-1,1), (1,-1), (3,0), mark: (end: "face", start: (symbol: ":)", flip: true, reverse: true), ))
+})
+
+#test-case({
+  import draw: *
+
+  line((0,-1), (0,1), stroke: green)
+
+  register-face()
+  mark((0,0), (+1,0), symbol: ":)", slant: 50%, anchor: "center")
+})
+
+#test-case({
+  import draw: *
+
+  register-face()
+  line((0,0), (3,0), mark: (end: (":)", ":)", ":)"), sep: -.3))
+})