old_contents: from unittest import TestCase
  from chipy8 import Chip8
  
  
  class Chip8Architecture(TestCase):
      def setUp(self):
          self.cpu = Chip8()
  
      def test_memory_length(self):
          'Chip8 has 4096 bytes of memory.'
          self.assertEqual(4096, len(self.cpu.memory))
  
      def test_memory_clear(self):
          'Chip8 must be initialized with a clear memory.'
          self.assertListEqual([0x00] * 4096, self.cpu.memory)
  
      def test_register_count(self):
          'Chip8 has 16 registers.'
          self.assertEqual(16, len(self.cpu.registers))
  
      def test_program_counter(self):
          'Chip8 has a program counter starting at 0x200.'
          self.assertEqual(0x200, self.cpu.program_counter)
  
      def test_index_register(self):
          'Chip8 has an index register.'
          self.assertEqual(0, self.cpu.index_register)
  
      def test_screen(self):
          'Chip8 has a 64 * 32 screen (2048 pixels).'
          self.assertEqual(2048, len(self.cpu.screen))
  
      def test_delay_timer(self):
          'Chip8 has a delay timer that counts to 0 at 60Hz.'
          self.assertEqual(0, self.cpu.delay_timer)
  
      def test_sound_timer(self):
          'Chip8 has a count down sound timer that beeps on non-zero value.'
          self.assertEqual(0, self.cpu.sound_timer)
  
      def test_stack(self):
          'Chip8 has a stack to return from jumps and calls.'
          self.assertIsInstance(self.cpu.stack, list)
  
      def test_keyboard(self):
          'Chip8 has a hex keyboard with 16 keys.'
          self.assertEqual(16, len(self.cpu.keyboard))
  
new_contents: from unittest import TestCase
  from chipy8 import Chip8
  
  
  class TestChip8Architecture(TestCase):
      def setUp(self):
          self.cpu = Chip8()
  
      def test_memory_length(self):
          'Chip8 has 4096 bytes of memory.'
          self.assertEqual(4096, len(self.cpu.memory))
  
      def test_memory_clear(self):
          'Chip8 must be initialized with a clear memory.'
          self.assertListEqual([0x00] * 4096, self.cpu.memory)
  
      def test_register_count(self):
          'Chip8 has 16 registers.'
          self.assertEqual(16, len(self.cpu.registers))
  
      def test_program_counter(self):
          'Chip8 has a program counter starting at 0x200.'
          self.assertEqual(0x200, self.cpu.program_counter)
  
      def test_index_register(self):
          'Chip8 has an index register.'
          self.assertEqual(0, self.cpu.index_register)
  
      def test_screen(self):
          'Chip8 has a 64 * 32 screen (2048 pixels).'
          self.assertEqual(2048, len(self.cpu.screen))
  
      def test_delay_timer(self):
          'Chip8 has a delay timer that counts to 0 at 60Hz.'
          self.assertEqual(0, self.cpu.delay_timer)
  
      def test_sound_timer(self):
          'Chip8 has a count down sound timer that beeps on non-zero value.'
          self.assertEqual(0, self.cpu.sound_timer)
  
      def test_stack(self):
          'Chip8 has a stack to return from jumps and calls.'
          self.assertIsInstance(self.cpu.stack, list)
  
      def test_keyboard(self):
          'Chip8 has a hex keyboard with 16 keys.'
          self.assertEqual(16, len(self.cpu.keyboard))
  
subject: Rename testcase name