tests: Don't fail silently if TestCase._pre_setup() raises an exception

[Thomas Güttler <hv@…>]

Hi,

up to now the test runner ends without displaying the results,
if there is an exception in TestCase._pre_setup():

Creating test database...
[cut]
No fixtures found.
temp /tmp/tmpacM5va
EError: Database test_foo couldn't be flushed. Possible reasons:
      * The database isn't running or isn't configured correctly.
      * At least one of the expected database tables doesn't exist.
      * The SQL was invalid.
    Hint: Look at the output of 'django-admin.py sqlflush'. That's the SQL this command wasn't able to run.
    The full error: current transaction is aborted, commands ignored until end of transaction block

This small patch passes the exception of _pre_setup() to the results of the testcase.

Otherwise it is hard to get the real error. The database error in _pre_setup()
is caused by the first test case. The output, or runnging the output of
'django-admin.py sqlflush' does not help, since the error can be specific to the
testdatabase.

Please apply this small patch. All unittests pass after applying it.

[Russell Keith-Magee]

(In [7023]) Fixed #6031 -- Added error handling for _pre_test in django.test.TestCase; exceptions during pre-test setup are now reported as test failures, rather than crashing the entire test framework. Thanks, Thomas Guttler <hv@…>.