Write a function to find the volume of a cube.
def volume_cube(l):
  volume = l * l * l
  return volume
<s>[INST]<<SYS>>Given a task and its code, generate test cases for the code.<</SYS>>Write a function to find the volume of a cube.
def volume_cube(l):
  volume = l * l * l
  return volume[/INST]assert volume_cube(3)==27
assert volume_cube(2)==8
assert volume_cube(5)==125</s>