 
     equals result.x, p1.x - p2.x
     equals result.y, p1.y - p2.y
+
+  test "#subtract$", ->
+    p = Point(8, 6)
+
+    p.subtract$(3, 4)
+
+    equals p.x, 5
+    equals p.y, 2
 
   test "#norm", ->
     p = Point(2, 0)


    equals result.x, p1.x + p2.x
    equals result.y, p1.y + p2.y

  test "#add with two arguments", ->
    point = Point(3, 7)

    equals result.x, point.x + x
    equals result.y, point.y + y

  test "#add$", ->
    p = Point(0, 0)

    p.add$(Point(3, 5))

    equals p.x, 3
    equals p.y, 5

    p.add$(2, 1)

    equals p.x, 5
    equals p.y, 6

  test "#subtract", ->
    p1 = Point(5, 6)
    p2 = Point(7, 5)
