cpython/Lib/test/test_free_threading/test_csv.py
Alper fb26d9c2ef
gh-116738: Make csv module thread-safe (gh-141365)
Added a critical section to protect the states of `ReaderObj` and `WriterObj` in the free-threading build. Without the critical sections, both new free-threading tests were crashing.
2025-11-21 11:22:31 -05:00

50 lines
1.5 KiB
Python

import csv
import io
import unittest
from test.support import threading_helper
from test.support.threading_helper import run_concurrently
NTHREADS = 10
@threading_helper.requires_working_threading()
class TestCSV(unittest.TestCase):
def test_concurrent_reader_next(self):
input_rows = [f"{i},{i},{i}" for i in range(50)]
input_stream = io.StringIO("\n".join(input_rows))
reader = csv.reader(input_stream)
output_rows = []
def read_row():
for row in reader:
self.assertEqual(len(row), 3)
output_rows.append(",".join(row))
run_concurrently(worker_func=read_row, nthreads=NTHREADS)
self.assertSetEqual(set(input_rows), set(output_rows))
def test_concurrent_writer_writerow(self):
output_stream = io.StringIO()
writer = csv.writer(output_stream)
row_per_thread = 10
expected_rows = []
def write_row():
for i in range(row_per_thread):
writer.writerow([i, i, i])
expected_rows.append(f"{i},{i},{i}")
run_concurrently(worker_func=write_row, nthreads=NTHREADS)
# Rewind to the start of the stream and parse the rows
output_stream.seek(0)
output_rows = [line.strip() for line in output_stream.readlines()]
self.assertEqual(len(output_rows), NTHREADS * row_per_thread)
self.assertListEqual(sorted(output_rows), sorted(expected_rows))
if __name__ == "__main__":
unittest.main()