old_contents: from fridge.memoryfs import MemoryFile
  
  
  class TestMemoryFile(object):
      def test_can_be_written(self):
          f = MemoryFile()
          f.write('test')
          f.flush()
          assert f.content == 'test'
  
new_contents: from fridge.memoryfs import MemoryFile
  
  
  class TestMemoryFile(object):
      def test_can_be_written(self):
          f = MemoryFile()
          f.write('test')
          f.flush()
          assert f.content == 'test'
  
      def test_close_flushes_content(self):
          f = MemoryFile()
          f.write('test')
          f.close()
          assert f.content == 'test'
  
      def test_can_be_reopened_and_read(self):
          f = MemoryFile()
          f.write('test')
          f.close()
          f.open()
          assert f.read() == 'test'
  
subject: Add more tests for MemoryFile.