code: def test_to_fortran(self):
      f = [IntFormat(10), IntFormat(12, 10), IntFormat(12, 10, 3)]
      res = ["(I10)", "(I12.10)", "(3I12.10)"]
  
      for i, j in zip(f, res):
          assert_equal(i.fortran_format, j)
  
imports: from __future__ import division, print_function, absolute_import
  import numpy
  from numpy.testing import assert_equal
  from pytest import raises
  from scipy.io.harwell_boeing._fortran_format_parser import FortranFormatParser, IntFormat, ExpFormat, BadFortranFormat, number_digits
label_desc: Use image node_id 1 for calling the TestIntFormat obj's underlying member method code with example usage: obj.test_to_fortran() without return types