code: def test_rvalue_fileno(self):
      self.tempfile()
      # Useless to check if same fileno, just checking if fct can be called
      self.run_test(
          """def _rvalue_fileno(filename):\n open(filename).fileno()""",
          self.filename,
          _rvalue_fileno=[str],
      )
  
imports: from tempfile import mkstemp
  from pythran.tests import TestEnv
  import unittest
  from pythran.typing import List
label_desc: Use image node_id 42 for calling the TestFile obj's underlying member method code with example usage: obj.test_rvalue_fileno() without return types