pytest migration: make pytest's parametrize functionality available To provide parameterized tests, a custom implementation is currently provided at kallithea/tests/parameterized.py because nose does not provide that out-of-the-box. pytest, on the other hand, does have a built-in 'parametrize' (note: different spelling) functionality. Therefore, once all tests have been converted to pytest, we can get rid of the custom 'parameterized' implementation. Also, the existing 'parameterized' implementation does not seem to work under pytest-style tests. This commit makes pytest's 'parametrize' decorator available alongside the custom 'parameterized' decorator. The names are confusing but it is the intention to kill the original 'parameterized' soon.