code: def test_readline():
      # Arrange
      for bytesmode in (True, False):
          with open(TEST_FILE, "rb" if bytesmode else "r") as fh:
              container = ContainerIO.ContainerIO(fh, 0, 120)
  
              # Act
              data = container.readline()
  
              # Assert
              if bytesmode:
                  data = data.decode()
              assert data == "This is line 1\n"
  
file_path: pillow-simd/Tests/test_file_container.py
imports: from PIL import ContainerIO, Image
  from .helper import hopper
label_desc: Use image node_id 9 for calling a global function with example usage: test_readline() without return types