There is no need to import testutils.unittest instead of simply
unittest. They are simple aliases. Use system unittest to be more
regular, consistent as well as idiomatic with the wider Python
community.
The syntax "except Exception, exc:" is deprecated. All Python versions
supported by psycopg2 support the newer, modern syntax. Forward
compatible with future Python versions.
Named cursors on old server versions have a different prefetch behaviour.
This has hidden me the supported range of the 24:00 time format.
Let's have another go at full testing...
`close()` is implicitly called by `__exit__()`, so an exit on error
would run a query on a inerr connection, causing another exception
hiding the original one. The fix is on `close()`, not on `__exit__()`,
because the semantic of the latter is simply to call the former.
Closes#262.
