test.cs

        [TestMethod]
        public void TestReflectCollision()
        {
            var position = Vector2.One;
            var speed = Vector2.One * -10.6f;
            var dT = 0.0016666f;

            var world = new World(Vector2.Zero);

            var wall = world.CreateRectangle(2F, 20f, 1f, new Vector2(-1F, 10f));
            wall.SetRestitution(1);
            wall.SetFriction(0);
            wall.FixedRotation = true;
            wall.IsBullet = true;


            var ball = world.CreateCircle(0.51f, 1f, position, BodyType.Dynamic);
            ball.LinearVelocity = speed;
            ball.SetRestitution(1);
            ball.SetFriction(0);
            ball.FixedRotation = true;
            ball.IsBullet = true;

            world.Step(dT*28);
            Assert.IsTrue(ball.LinearVelocity.X < -10 && ball.LinearVelocity.Y < -10, ball.LinearVelocity.ToString());
            world.Step(dT);

            // this one fails
            Assert.IsTrue(ball.LinearVelocity.X > 10 && ball.LinearVelocity.Y > 10, ball.LinearVelocity.ToString());
        }

I'm wondering how to get rid of this issue?