def test_Swarm_hatch():
swarm = Swarm()
swarm.hatch(50,behaviour)
assert_equal(swarm.size,50)
assert_equal(len(swarm.members),50)
for boid in swarm.members:
assert_greater(boid.position[0],-450)
assert_less(boid.position[0],50)
assert_greater(boid.position[1],300)
assert_less(boid.position[1],600)
assert_greater(boid.velocity[0],0)
assert_less(boid.velocity[0],10)
assert_greater(boid.velocity[1],-20)
assert_less(boid.velocity[1],20)
