'run_cell(silent=True) doesn\'t advance execution_count'

def test_silent_noadvance(self):

    ec = ip.execution_count
    ip.run_cell('1', store_history=True, silent=True)
    self.assertEqual(ec, ip.execution_count)
    ip.run_cell('1', store_history=True)
    self.assertEqual((ec + 1), ip.execution_count)
