Unit test execution is slow with real SQLite database

[Ryan J Ollos]

First mentioned in comment:20:ticket:11512, here is what I get on 1.0-stable

$ make unit-testPython version: Python 2.7.4
figleaf: 
coverage: 
PYTHONPATH=.:
TRAC_TEST_DB_URI=
server-options= -p 8000 -a '*,~/tracenvs/htdigest.realm,realm' -r -e ~/tracenvs
python setup.py egg_info
running egg_info
writing requirements to Trac.egg-info/requires.txt
writing Trac.egg-info/PKG-INFO
writing top-level names to Trac.egg-info/top_level.txt
writing dependency_links to Trac.egg-info/dependency_links.txt
writing entry points to Trac.egg-info/entry_points.txt
reading manifest file 'Trac.egg-info/SOURCES.txt'
writing manifest file 'Trac.egg-info/SOURCES.txt'
python ./trac/test.py --skip-functional-tests 
...
Ran 1545 tests in 37.987s

OK
$ make db=sqlite unit-test
Python version: Python 2.7.4
figleaf: 
coverage: 
PYTHONPATH=.:
TRAC_TEST_DB_URI=sqlite:test.db
server-options= -p 8000 -a '*,~/tracenvs/htdigest.realm,realm' -r -e ~/tracenvs
python setup.py egg_info
running egg_info
writing requirements to Trac.egg-info/requires.txt
writing Trac.egg-info/PKG-INFO
writing top-level names to Trac.egg-info/top_level.txt
writing dependency_links to Trac.egg-info/dependency_links.txt
writing entry points to Trac.egg-info/entry_points.txt
reading manifest file 'Trac.egg-info/SOURCES.txt'
writing manifest file 'Trac.egg-info/SOURCES.txt'
python ./trac/test.py --skip-functional-tests 
...
Ran 1545 tests in 82.705s

OK

The results seem to be the same on 0.12-stable with and without db=sqlite.