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])