Testupgrade

[prculley]

This adds some tests of the db upgrade process. I have added several small dbs created with older versions of Gramps.
The imports_test code was updated to allow zips of these dbs as inputs to the test. I chose to modify imports_test as there was substantial code reuse if I created a new module.

As usual the test compares the extracted and loaded db with the matching Gramps XML file and reports any differences. This should fail if the upgrade code crashes or misses something important.

I've tested this on top of PR#1992 and it seems to work.

[emyoulation]

The imports_test code was updated to allow zips of these dbs as inputs to the test.

Nice! I assume that this accepts the backups automatically generated during a Convert schema?

[prculley]

It does not accept zips created during upgrade directly. You have to massage the names of the zip and the db directory inside the zip to says something like "imp_???????" in order for the test files to be recognized. And of course, you need a .gramps file with the same name to compare the db with.