support running tests for an installed version without causing allmydata.test.test_runner.BinTahoe.test_the_right_code to fail

[davidsarah]

The intended way to run tests for an OS package-manager-installed copy of Tahoe-LAFS is tahoe debug trial (which uses the installed tahoe script on the PATH).

This fails with the following error:

[FAIL]
Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.7/allmydata/test/test_runner.py", line 119, in test_the_right_code
    self._check_right_code(srcfile)
  File "/usr/lib/pymodules/python2.7/allmydata/test/test_runner.py", line 116, in _check_right_code
    self.fail(msg)
twisted.trial.unittest.FailTest: We seem to be testing the code at '/usr/lib/pymodules',
(according to the source filename '/usr/lib/pymodules/python2.7/allmydata/__init__.pyc'),
but expected to be testing the code at '/home/eutopia'.
Please run the tests from the root of the Tahoe-LAFS distribution.

allmydata.test.test_runner.BinTahoe.test_the_right_code

because that test doesn't know where the code is supposed to be located. It is OK for the test to be skipped in this case.

[davidsarah]

​https://bugs.launchpad.net/ubuntu/+source/pycryptopp/+bug/811721/comments/18 is an example of such a failure. (Note that the launchpad bug is otherwise unrelated.)

[davidsarah]

As nejucomo points out on #tahoe-lafs, it's ugly to need to run the tests with the base of the distribution as the current directory. Perhaps there should be an explicit option to tell 'tahoe debug trial' where the code it is supposed to be testing is. (It could request to be rerun with that option if the current directory does not look like it is a Tahoe distribution.)