old_contents: # -*- coding: utf-8 -*-
  import unittest
  
  from rename import is_binary
  
  
  class TestIsBinary(unittest.TestCase):
  
      binary_file_path = 'tests/tests_files/binary_file'
  
      def setUp(self):
          self.create_binary_file()
  
      def create_binary_file(self):
          "create a binary file to test with"
  
          with open(self.binary_file_path, 'wb') as bf:
              bf.write(bytearray([1, 2, 3]))
  
      def test_is_binary_should_return_true_if_binary_file(self):
          "test if is_binary returns true when checking a binary file"
          self.assertTrue(is_binary(self.binary_file_path))
  
      def tearDown(self):
          self.remove_binary_file()
  
      def remove_binary_file(self):
          "remove the binary file created for tests"
          import os
          os.remove(self.binary_file_path)
  
new_contents: # -*- coding: utf-8 -*-
  import unittest
  
  from rename import is_binary
  
  
  class TestIsBinary(unittest.TestCase):
  
      binary_file_path = 'tests/tests_files/binary_file'
  
      def setUp(self):
          "This will run before any test in this class"
          self.create_binary_file()
  
      def tearDown(self):
          "This will run after any test in this class"
          self.remove_binary_file()
  
      def create_binary_file(self):
          "create a binary file to test with"
  
          with open(self.binary_file_path, 'wb') as bf:
              bf.write(bytearray([1, 2, 3]))
  
      def remove_binary_file(self):
          "remove the binary file created for tests"
          import os
          os.remove(self.binary_file_path)
  
      def test_is_binary_should_return_true_if_binary_file(self):
          "test if is_binary returns true when checking a binary file"
          self.assertTrue(is_binary(self.binary_file_path))
  
subject: add more docstrings on the tests