[issue27447] python -m doctest file_with_no_py_extension # silently fails

[towb]

New submission from towb:

Command line tools usually use the shebang and don't have a .py extension. This breaks the `python -m doctest` shortcut for testmod().

Getting it to work is probably ugly, but there should be a useful message. Currently it's just a NameError for every function, which is very confusing.

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components: Library (Lib)
messages: 269781
nosy: towb
priority: normal
severity: normal
status: open
title: python -m doctest file_with_no_py_extension # silently fails
type: behavior
versions: Python 3.5

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue27447>
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