IPython/core/tests/test_ultratb.py

"""Tests for IPython.core.ultratb
"""

import os.path
import unittest

from IPython.testing import tools as tt
from IPython.utils.syspathcontext import prepended_to_syspath
from IPython.utils.tempdir import TemporaryDirectory

ip = get_ipython()

file_1 = """1
2
3
def f():
  1/0
"""

file_2 = """def f():
  1/0
"""

class ChangedPyFileTest(unittest.TestCase):
    def test_changing_py_file(self):
        """Traceback produced if the line where the error occurred is missing?
        
        https://github.com/ipython/ipython/issues/1456
        """
        with TemporaryDirectory() as td:
            fname = os.path.join(td, "foo.py")
            with open(fname, "w") as f:
                f.write(file_1)
            
            with prepended_to_syspath(td):
                ip.run_cell("import foo")
            
            with tt.AssertPrints("ZeroDivisionError"):
                ip.run_cell("foo.f()")
            
            # Make the file shorter, so the line of the error is missing.
            with open(fname, "w") as f:
                f.write(file_2)
            
            # For some reason, this was failing on the *second* call after
            # changing the file, so we call f() twice.
            with tt.AssertNotPrints("Internal Python error", channel='stderr'):
                with tt.AssertPrints("ZeroDivisionError"):
                    ip.run_cell("foo.f()")
                with tt.AssertPrints("ZeroDivisionError"):
                    ip.run_cell("foo.f()")