Add concave polygon contains specs

lib/components/polygon.test.js

@@ -100,6 +100,33 @@ describe('Polygon', () => {
       }
     })
 
-    // TODO@v1: add concave polygon for tests
+    describe('bowtie', () => {
+      const poly = new Polygon({
+        points: [
+          vec2(0, 0),
+          vec2(5, 2),
+          vec2(10, 0),
+          vec2(10, 8),
+          vec2(5, 6),
+          vec2(0, 8),
+        ],
+      })
+
+      const tests = [
+        [vec2(1, 1), true],
+        [vec2(1, 7), true],
+        [vec2(5, 5), true],
+        [vec2(9, 1), true],
+        [vec2(9, 7), true],
+        [vec2(5, 1), false],
+        [vec2(5, 7), false],
+      ]
+
+      for (const [point, expected] of tests) {
+        it(`returns ${expected} for ${point}`, () => {
+          assert.strictEqual(poly.contains(point), expected)
+        })
+      }
+    })
   })
 })