IPython Documentation

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Module: utils.doctestreload

A utility for handling the reloading of doctest.


IPython.utils.doctestreload.dhook_wrap(func, *a, **k)

Wrap a function call in a sys.displayhook controller.

Returns a wrapper around func which calls func, with all its arguments and keywords unmodified, using the default sys.displayhook. Since IPython modifies sys.displayhook, it breaks the behavior of certain systems that rely on the default behavior, notably doctest.


Properly reload doctest to reuse it interactively.

This routine:

  • imports doctest but does NOT reload it (see below).
  • resets its global ‘master’ attribute to None, so that multiple uses of

the module interactively don’t produce cumulative reports.

  • Monkeypatches its core test runner method to protect it from IPython’s

modified displayhook. Doctest expects the default displayhook behavior deep down, so our modification breaks it completely. For this reason, a hard monkeypatch seems like a reasonable solution rather than asking users to manually use a different doctest runner when under IPython.


This function used to reload doctest, but this has been disabled because reloading doctest unconditionally can cause massive breakage of other doctest-dependent modules already in memory, such as those for IPython’s own testing system. The name wasn’t changed to avoid breaking people’s code, but the reload call isn’t actually made anymore.