def test_z2i(self):
"""
Should convert between z indices and coordinates and back
"""
r1 = (-10, -20, -30)
r2 = (10, 20, 30)
vm = VM(r1=r1, r2=r2, dx=1, dy=1, dz=1)
iz = vm.z2i([vm.r1[2]])[0]
z = vm.i2z([iz])[0]
self.assertEqual(iz, 0)
self.assertEqual(z, vm.r1[2])
iz = vm.z2i([vm.r2[2]])[0]
z = vm.i2z([iz])[0]
self.assertEqual(iz, vm.nz - 1)
self.assertEqual(z, vm.r2[2])
