Between now and the June primary your county must publicly test its voting machines. You can participate–and not just by watching. You can call the county auditor for the schedule or ask your political party chair who should have been notified as well. Contact the Rs or the Ds where you live. Iowa code chapter 52 provides for a test using "a pre-audited group of ballots" including a provision that "Any observer may submit an additional test group of ballots which, if so submitted, shall also be tested." Your test group is limited to ten ballots, but they may be the only independently created ballots in the test. It is common for officials to run canned tests provided for them by the same company that sold them the machine and then set up the ballot definition for the next election. In that case it is only the programmer testing himself.