[Python-Dev] Looking for an "import" expert

[Guido van Rossum]

If the tests are run "the modern way" (python ../Lib/test/regrtest.py)
then the test module is the script directory and it is on the path, so
"import test_support" sees and loads a toplevel module test_support.
Then "import test.test_support" sees a package test with a
test_support submodule which is assumed to be a different one, so it
is loaded again.

But if the tests are run via "import test.autotest" (or "import
test.regrtest; test.regrtest.main()" the "import test_support" knows
that the importing module is in the test package, so it first tries to
import the test_support submodule from that package, so
test.test_support and (plain) test_support are the same.

Conclusion: inside the test package, never refer explicitly to the
test package.  Always use "import test_support".  Never "import
test.test_support" or "from test.test_support import verbose" or "from
test import test_support".

This is one for the README!

I've fixed this by checking in a small patch to test_getopt.py and the
corresponding output file (because of the bug, the output file was
produced under verbose mode).

--Guido van Rossum (home page: http://www.pythonlabs.com/~guido/)