code: def test_foreign_buffer():
      ctx = global_context
      dtype = np.dtype(np.uint8)
      size = 10
      hbuf = cuda.new_host_buffer(size * dtype.itemsize)
  
      # test host buffer memory reference counting
      rc = sys.getrefcount(hbuf)
      fbuf = ctx.foreign_buffer(hbuf.address, hbuf.size, hbuf)
      assert sys.getrefcount(hbuf) == rc + 1
      del fbuf
      assert sys.getrefcount(hbuf) == rc
  
      # test postponed deallocation of host buffer memory
      fbuf = ctx.foreign_buffer(hbuf.address, hbuf.size, hbuf)
      del hbuf
      fbuf.copy_to_host()
  
      # test deallocating the host buffer memory making it inaccessible
      hbuf = cuda.new_host_buffer(size * dtype.itemsize)
      fbuf = ctx.foreign_buffer(hbuf.address, hbuf.size)
      del hbuf
      with pytest.raises(pa.ArrowIOError, match=("Cuda error ")):
          fbuf.copy_to_host()
  
imports: import sys
  import sysconfig
  import pytest
  import pyarrow
  import numpy
label_desc: Use image node_id 9 for calling a global function with example usage: test_foreign_buffer() without return types