Repro container for ipython/ipython#12203

Dockerfile

from ubuntu:18.04
run apt update
run apt install -y python3.8 python3-pip
run python3.8 -m pip install ipdb ipython  

run echo '\
import unittest\n\
\n\
\n\
class Test(unittest.TestCase):\n\
    def test(self):\n\
        import ipdb; ipdb.set_trace()\n\
        for i in range(1, 10):\n\
            self.assertEqual(i, i)\n\
\n\
\n\
def main():\n\
    import tracemalloc\n\
\n\
    tracemalloc.start(25)\n\
    unittest.main()\n\
\n\
\n\
if __name__ == "__main__":\n\
    main()\n' > /test.py

cmd python3.8 /test.py