BUG: fix coverage

[ThibTrip]

Coverage does not work as expected because we need to do one pytest and not 3. We could parameterize with multiple engines by changing the pytest command to:

pytest -s -v pangres --cov=./pangres --sqlite_conn=$sqlite_conn --pg_conn=$pg_conn --mysql_conn=$mysql_conn

However the order is not how it should be for our tests:

test_1[engine0,schema]
test_1[engine1,schema]
test_2[engine0,schema]
test_2[engine1,schema]

Should be:
test_1[engine0,schema]
test_2[engine0,schema]
test_1[engine1,schema]
test_2[engine1,schema]

I will try to fix this with classes as proposed here: https://stackoverflow.com/a/31966811/10551772

Not sure how to do this but I'll try. If anyone wants to give me a quick example so I can reproduce it on all tests that would be appreciated 👍 !

I think the configuration I locally updated in conftest.py is correct (see below) so we just have to change the tests.

def pytest_addoption(parser):
    parser.addoption('--sqlite_conn', action="store")
    parser.addoption('--pg_conn', action="store")
    parser.addoption('--mysql_conn', action="store")
    parser.addoption('--pg_schema', action='store', default=None)


def pytest_generate_tests(metafunc):
    # This is called for every test. Only get/set command line arguments
    # if the argument is specified in the list of test "fixturenames".
    conn_strings = {'sqlite':metafunc.config.option.sqlite_conn,
                    'pg':metafunc.config.option.pg_conn,
                    'mysql':metafunc.config.option.mysql_conn}
    engines = []
    schemas = []
    for db_type, conn_string in conn_strings.items():
        schema = metafunc.config.option.pg_schema if db_type == 'pg' else None
        engine = create_engine(conn_string)
        schemas.append(schema)
        engines.append(engine)
    metafunc.parametrize("engine", engines)
    metafunc.parametrize("schema", schemas)