Function expectMutation

test/app/lib/world/vector.spec.js:81–86

(fn)

  return it('mutates when not in player code', function() {
    const expectMutation = function(fn) {
      const v = new Vector(5, 5);
      const v2 = fn(v);
      expect(v.x).not.toEqual(5);
      return expect(v).toBe(v2);
    };

    expectMutation(v => v.normalize());
    expectMutation(v => v.limit(2));