old_contents: import unittest
  from jnius import autoclass
  
  class StringArgumentForByteArrayTest(unittest.TestCase):
  
      def test_string_arg_for_byte_array(self):
          # the ByteBuffer.wrap() accept only byte[].
          ByteBuffer = autoclass('java.nio.ByteBuffer')
          self.assertIsNotNone(ByteBuffer.wrap('hello world'))
  
new_contents: import unittest
  from jnius import autoclass
  
  class StringArgumentForByteArrayTest(unittest.TestCase):
  
      def test_string_arg_for_byte_array(self):
          # the ByteBuffer.wrap() accept only byte[].
          ByteBuffer = autoclass('java.nio.ByteBuffer')
          self.assertIsNotNone(ByteBuffer.wrap('hello world'))
  
      def test_string_arg_with_signed_char(self):
          ByteBuffer = autoclass('java.nio.ByteBuffer')
          self.assertIsNotNone(ByteBuffer.wrap('\x00\xffHello World\x7f'))
  
subject: add a test with signed char to ensure it still working