The test for add_row() does not revert changes to the pre-test state.
Reproducing the bug consists of running twice in succession the following test:
$ nosetests -x -s tests/test.py:WorksheetTest.test_properties
It should always fail the second time, since the test spreadsheet has now one line and four columns more than before.
fix for add_row() test that did not revert changes to pre-test state
Great! Thank you Javier, that was annoying bug.
Guess who was the clown who introduced it...
Ooops, I thought it was me, hehe )