code: def test_runnable(self):
      cwd = os.path.dirname(__file__)
      regex = re.compile(r"^test_.*\.py$")
      for dirpath, dirnames, filenames in os.walk(cwd):
          for filename in filenames:
              if not regex.match(filename):
                  continue
              path = os.path.join(dirpath, filename)
              with io.open(path, encoding="utf-8") as f:
                  source = f.read()
              self.assertIn(
                  "testing.run_module(__name__, __file__)",
                  source,
                  """{0} is not runnable.
  Call testing.run_module at the end of the test.""".format(
                      path
                  ),
              )
  
file_path: chainer/tests/chainer_tests/test_runnable.py
imports: import io
  import os
  import re
  import unittest
  from chainer import testing
label_desc: Use image node_id 1 for calling the TestRunnable obj's underlying member method code with example usage: obj.test_runnable() without return types