code: def test_1bit():
      # Test that 1-bit arrays convert to numpy and back
      # See: https://github.com/python-pillow/Pillow/issues/350
      arr = numpy.array([[1, 0, 0, 1, 0], [0, 1, 0, 0, 0]], "u1")
      img = Image.fromarray(arr * 255).convert("1")
      assert img.mode == "1"
      arr_back = numpy.array(img)
      numpy.testing.assert_array_equal(arr, arr_back)
  
file_path: pillow/Tests/test_numpy.py
imports: from __future__ import annotations
  import warnings
  import pytest
  from PIL import Image
  from .helper import assert_deep_equal, assert_image, hopper, skip_unless_feature
label_desc: Use image node_id 6 for calling a global function with example usage: test_1bit() without return types