Run doctests in tox.

tox.ini

@@ -21,3 +21,4 @@ commands =
   driver-mock: mvn -Dmaven.repo.local={toxworkdir}/shared/.m2/repository -f mockdriver/pom.xml install
   driver-mock: jip install org.jaydebeapi:mockdriver:1.0-SNAPSHOT
   {envbindir}/python test/testsuite.py {env:TESTNAME}
+  driver-hsqldb: {envbindir}/python test/doctests.py