doctest currently has 8 "data" files used for testing that are spread across Lib/test (in addition to the main test files test_doctest.py and test_doctest2.py):

doctest_aliases.py
sample_doctest.py
sample_doctest_no_docstrings.py
sample_doctest_no_doctests.py
test_doctest.txt
test_doctest2.txt
test_doctest3.txt
test_doctest4.txt

This issue is to move these files into a common subdirectory of Lib/test (e.g. Lib/test/doctest).  This will simplify the organization of doctest's tests (e.g. by making the supporting files easier to discover) and reduce clutter in the main test directory.

Note that test_zipimport_support (and perhaps also test_pyclbr) will also require changes.

This issue came out of discussions with R. David Murray in the context of working on issue 14649.