Think testing software isn't exciting or that it never cause controversy?

Think again.

https://www.zdnet.com/article/draeger-breathalyzer-breath-test-convictions/

In order to produce a result, the Alcotest 9510 uses two sensors to measure alcohol content in a breath sample: An infrared beam that measures how much light goes through the breath, and a fuel cell that measures the electrical current of the sample. The results should be about the same and within a small margin of error -- usually within a thousandth of a decimal point. If the results are too far apart, the test will be rejected.

But the report said that under some conditions the breathalyzer can return an inflated reading -- a result that could also push a person over the legal limit.