code: def test_scalar_search_armijo(self):
      for name, phi, derphi, old_phi0 in self.scalar_iter():
          s, phi1 = ls.scalar_search_armijo(phi, phi(0), derphi(0))
          assert_fp_equal(phi1, phi(s), name)
          assert_armijo(s, phi, err_msg="%s %g" % (name, old_phi0))
  
imports: from numpy.testing import assert_, assert_equal, assert_array_almost_equal, assert_array_almost_equal_nulp, assert_warns, suppress_warnings
  import scipy.optimize.linesearch
  from scipy.optimize.linesearch import LineSearchWarning
  import numpy
label_desc: Use image node_id 13 for calling the TestLineSearch obj's underlying member method code with example usage: obj.test_scalar_search_armijo() without return types