old_contents: import unittest
  import numpy as np
  import pytest
  from desc.grid import LinearGrid, ConcentricGrid
  from desc.equilibrium import Equilibrium
  from desc.objectives import (
      ObjectiveFunction,
      FixedBoundaryR,
      FixedBoundaryZ,
      FixedPressure,
      FixedIota,
      FixedPsi,
      LCFSBoundary,
      RadialForceBalance,
      HelicalForceBalance,
      Energy,
  )
  
  
  class TestObjectiveFunction(unittest.TestCase):
      """Test ObjectiveFunction class."""
  
      def test_something(self):
          """Test something."""
          pass
  
new_contents: import unittest
  import numpy as np
  from desc.equilibrium import Equilibrium
  from desc.objectives import (
      Energy,
      Volume,
      AspectRatio,
      ToroidalCurrent,
      ToroidalCurrentDensity,
      QuasisymmetryBoozer,
      QuasisymmetryTwoTerm,
      QuasisymmetryTripleProduct,
  )
  
  
  class TestObjectiveFunction(unittest.TestCase):
      """Test ObjectiveFunction class."""
  
      def test_volume(self):
          eq = Equilibrium()
          obj = Volume(target=10 * np.pi ** 2, weight=1 / np.pi ** 2)
          obj.build(eq)
          V = obj.compute(eq.R_lmn, eq.Z_lmn)
          np.testing.assert_allclose(V, 10)
  
      def test_aspect_ratio(self):
          eq = Equilibrium()
          obj = AspectRatio(target=5, weight=2)
          obj.build(eq)
          AR = obj.compute(eq.R_lmn, eq.Z_lmn)
          np.testing.assert_allclose(AR, 10)
  
      def test_energy(self):
          eq = Equilibrium()
          obj = Energy(target=0, weight=(4 * np.pi * 1e-7))
          obj.build(eq)
          W = obj.compute(eq.R_lmn, eq.Z_lmn, eq.L_lmn, eq.i_l, eq.p_l, eq.Psi)
          np.testing.assert_allclose(W, 10)
  
      def test_toroidal_current(self):
          eq = Equilibrium()
          obj = ToroidalCurrent(target=1, weight=2)
          obj.build(eq)
          I = obj.compute(eq.R_lmn, eq.Z_lmn, eq.L_lmn, eq.i_l, eq.Psi)
          np.testing.assert_allclose(I, -2)
  
      def test_toroidal_current_density(self):
          eq = Equilibrium()
          obj = ToroidalCurrentDensity(target=1, weight=2)
          obj.build(eq)
          Jt = obj.compute(eq.R_lmn, eq.Z_lmn, eq.L_lmn, eq.i_l, eq.Psi)
          np.testing.assert_allclose(Jt, -2)
  
      def test_qs_boozer(self):
          eq = Equilibrium()
          obj = QuasisymmetryBoozer()
          obj.build(eq)
          fb = obj.compute(eq.R_lmn, eq.Z_lmn, eq.L_lmn, eq.i_l, eq.Psi)
          np.testing.assert_allclose(fb, 0)
  
      def test_qs_twoterm(self):
          eq = Equilibrium()
          obj = QuasisymmetryTwoTerm()
          obj.build(eq)
          fb = obj.compute(eq.R_lmn, eq.Z_lmn, eq.L_lmn, eq.i_l, eq.Psi)
          np.testing.assert_allclose(fb, 0)
  
      def test_qs_tp(self):
          eq = Equilibrium()
          obj = QuasisymmetryTripleProduct()
          obj.build(eq)
          fb = obj.compute(eq.R_lmn, eq.Z_lmn, eq.L_lmn, eq.i_l, eq.Psi)
          np.testing.assert_allclose(fb, 0)
  
subject: Add basic tests for objective functions